Morten Sørlie, Malene Billeskov Keller, Peter Westh
{"title":"The interplay between lytic polysaccharide monooxygenases and glycoside hydrolases.","authors":"Morten Sørlie, Malene Billeskov Keller, Peter Westh","doi":"10.1042/EBC20220156","DOIUrl":"https://doi.org/10.1042/EBC20220156","url":null,"abstract":"<p><p>In nature, enzymatic degradation of recalcitrant polysaccharides such as chitin and cellulose takes place by a synergistic interaction between glycoside hydrolases (GHs) and lytic polysaccharide monooxygenases (LPMOs). The two different families of carbohydrate-active enzymes use two different mechanisms when breaking glycosidic bonds between sugar moieties. GHs employ a hydrolytic activity and LPMOs are oxidative. Consequently, the topologies of the active sites differ dramatically. GHs have tunnels or clefts lined with a sheet of aromatic amino acid residues accommodating single polymer chains being threaded into the active site. LPMOs are adapted to bind to the flat crystalline surfaces of chitin and cellulose. It is believed that the LPMO oxidative mechanism provides new chain ends that the GHs can attach to and degrade, often in a processive manner. Indeed, there are many reports of synergies as well as rate enhancements when LPMOs are applied in concert with GHs. Still, these enhancements vary in magnitude with respect to the nature of the GH and the LPMO. Moreover, impediment of GH catalysis is also observed. In the present review, we discuss central works where the interplay between LPMOs and GHs has been studied and comment on future challenges to be addressed to fully use the potential of this interplay to improve enzymatic polysaccharide degradation.</p>","PeriodicalId":11812,"journal":{"name":"Essays in biochemistry","volume":"67 3","pages":"551-559"},"PeriodicalIF":6.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9333332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mucin utilization by gut microbiota: recent advances on characterization of key enzymes.","authors":"Grete Raba, Ana S Luis","doi":"10.1042/EBC20220121","DOIUrl":"https://doi.org/10.1042/EBC20220121","url":null,"abstract":"<p><p>The gut microbiota interacts with the host through the mucus that covers and protects the gastrointestinal epithelium. The main component of the mucus are mucins, glycoproteins decorated with hundreds of different O-glycans. Some microbiota members can utilize mucin O-glycans as carbons source. To degrade these host glycans the bacteria express multiple carbohydrate-active enzymes (CAZymes) such as glycoside hydrolases, sulfatases and esterases which are active on specific linkages. The studies of these enzymes in an in vivo context have started to reveal their importance in mucin utilization and gut colonization. It is now clear that bacteria evolved multiple specific CAZymes to overcome the diversity of linkages found in O-glycans. Additionally, changes in mucin degradation by gut microbiota have been associated with diseases like obesity, diabetes, irritable bowel disease and colorectal cancer. Thereby understanding how CAZymes from different bacteria work to degrade mucins is of critical importance to develop new treatments and diagnostics for these increasingly prevalent health problems. This mini-review covers the recent advances in biochemical characterization of mucin O-glycan-degrading CAZymes and how they are connected to human health.</p>","PeriodicalId":11812,"journal":{"name":"Essays in biochemistry","volume":"67 3","pages":"345-353"},"PeriodicalIF":6.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10154618/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9408135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Revisiting the role of electron donors in lytic polysaccharide monooxygenase biochemistry.","authors":"Glyn R Hemsworth","doi":"10.1042/EBC20220164","DOIUrl":"https://doi.org/10.1042/EBC20220164","url":null,"abstract":"<p><p>The plant cell wall is rich in carbohydrates and many fungi and bacteria have evolved to take advantage of this carbon source. These carbohydrates are largely locked away in polysaccharides and so these organisms deploy a range of enzymes that can liberate individual sugars from these challenging substrates. Glycoside hydrolases (GHs) are the enzymes that are largely responsible for bringing about this sugar release; however, 12 years ago, a family of enzymes known as lytic polysaccharide monooxygenases (LPMOs) were also shown to be of key importance in this process. LPMOs are copper-dependent oxidative enzymes that can introduce chain breaks within polysaccharide chains. Initial work demonstrated that they could activate O2 to attack the substrate through a reaction that most likely required multiple electrons to be delivered to the enzyme. More recently, it has emerged that LPMO kinetics are significantly improved if H2O2 is supplied to the enzyme as a cosubstrate instead of O2. Only a single electron is required to activate an LPMO and H2O2 cosubstrate and the enzyme has been shown to catalyse multiple turnovers following the initial one-electron reduction of the copper, which is not possible if O2 is used. This has led to further studies of the roles of the electron donor in LPMO biochemistry, and this review aims to highlight recent findings in this area and consider how ongoing research could impact our understanding of the interplay between redox processes in nature.</p>","PeriodicalId":11812,"journal":{"name":"Essays in biochemistry","volume":"67 3","pages":"585-595"},"PeriodicalIF":6.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10154616/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9400470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hemicellulolytic enzymes in lignocellulose processing.","authors":"Heidi Østby, Anikó Várnai","doi":"10.1042/EBC20220154","DOIUrl":"https://doi.org/10.1042/EBC20220154","url":null,"abstract":"<p><p>Lignocellulosic biomass is the most abundant source of carbon-based material on a global basis, serving as a raw material for cellulosic fibers, hemicellulosic polymers, platform sugars, and lignin resins or monomers. In nature, the various components of lignocellulose (primarily cellulose, hemicellulose, and lignin) are decomposed by saprophytic fungi and bacteria utilizing specialized enzymes. Enzymes are specific catalysts and can, in many cases, be produced on-site at lignocellulose biorefineries. In addition to reducing the use of often less environmentally friendly chemical processes, the application of such enzymes in lignocellulose processing to obtain a range of specialty products can maximize the use of the feedstock and valorize many of the traditionally underutilized components of lignocellulose, while increasing the economic viability of the biorefinery. While cellulose has a rich history of use in the pulp and paper industries, the hemicellulosic fraction of lignocellulose remains relatively underutilized in modern biorefineries, among other reasons due to the heterogeneous chemical structure of hemicellulose polysaccharides, the composition of which varies significantly according to the feedstock and the choice of pretreatment method and extraction solvent. This paper reviews the potential of hemicellulose in lignocellulose processing with focus on what can be achieved using enzymatic means. In particular, we discuss the various enzyme activities required for complete depolymerization of the primary hemicellulose types found in plant cell walls and for the upgrading of hemicellulosic polymers, oligosaccharides, and pentose sugars derived from hemicellulose depolymerization into a broad spectrum of value-added products.</p>","PeriodicalId":11812,"journal":{"name":"Essays in biochemistry","volume":"67 3","pages":"533-550"},"PeriodicalIF":6.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10160854/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10080793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuhua Gong, Annie Lebreton, Feng Zhang, Francis Martin
{"title":"Role of carbohydrate-active enzymes in mycorrhizal symbioses.","authors":"Yuhua Gong, Annie Lebreton, Feng Zhang, Francis Martin","doi":"10.1042/EBC20220127","DOIUrl":"https://doi.org/10.1042/EBC20220127","url":null,"abstract":"<p><p>Mycorrhizal fungi form mutually beneficial interactions with a wide range of terrestrial plants. During this symbiosis, the associated fungus provides mineral nutrients, such as phosphorus and nitrogen, to its host plant in exchange of photosynthesis-derived carbohydrates. Genome sequencing of mycorrhizal fungi has shown that arbuscular mycorrhizal fungi and ectomycorrhizal fungi have a restricted set of plant-cell wall degrading enzymes (PCWDE) genes, while orchid and ericoid mycorrhizal fungi have an extended PCWDE repertoire similar to soil decomposers and wood-decay fungi. On the other hand, mycorrhizal fungi have retained a substantial set of carbohydrate active enzymes (CAZymes) acting on microbial polysaccharides. Functional analysis has shown that several of the remaining PCWDEs are involved in the fungal root colonization and establishment of the symbiotic interface. In this review, we highlight the current knowledge on the evolution and function of PCWDEs in mycorrhizal fungi.</p>","PeriodicalId":11812,"journal":{"name":"Essays in biochemistry","volume":"67 3","pages":"471-478"},"PeriodicalIF":6.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9338127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Copper radical oxidases: galactose oxidase, glyoxal oxidase, and beyond!","authors":"Jessica K Fong, Harry Brumer","doi":"10.1042/EBC20220124","DOIUrl":"https://doi.org/10.1042/EBC20220124","url":null,"abstract":"<p><p>The copper radical oxidases (CROs) are an evolutionary and functionally diverse group of enzymes established by the historically significant galactose 6-oxidase and glyoxal oxidase from fungi. Inducted in 2013, CROs now constitute Auxiliary Activity Family 5 (AA5) in the Carbohydrate-Active Enzymes (CAZy) classification. CROs catalyse the two-electron oxidation of their substrates using oxygen as the final electron acceptor and are particularly distinguished by a cross-linked tyrosine-cysteine co-factor that is integral to radical stabilization. Recently, there has been a significant increase in the biochemically and structurally characterized CROs, which has revealed an expanded natural diversity of catalytic activities in the family. This review provides a brief historical introduction to CRO biochemistry and structural biology as a foundation for an update on current advances in CRO enzymology, biotechnology, and biology across kingdoms of life.</p>","PeriodicalId":11812,"journal":{"name":"Essays in biochemistry","volume":"67 3","pages":"597-613"},"PeriodicalIF":6.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9338131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Glucuronoyl esterases - enzymes to decouple lignin and carbohydrates and enable better utilization of renewable plant biomass.","authors":"Johan Larsbrink, Leila Lo Leggio","doi":"10.1042/EBC20220155","DOIUrl":"https://doi.org/10.1042/EBC20220155","url":null,"abstract":"<p><p>Glucuronoyl esterases (GEs) are microbial enzymes able to cleave covalent linkages between lignin and carbohydrates in the plant cell wall. GEs are serine hydrolases found in carbohydrate esterase family 15 (CE15), which belongs to the large α/β hydrolase superfamily. GEs have been shown to reduce plant cell wall recalcitrance by hydrolysing the ester bonds found between glucuronic acid moieties on xylan polysaccharides and lignin. In recent years, the exploration of CE15 has broadened significantly and focused more on bacterial enzymes, which are more diverse in terms of sequence and structure to their fungal counterparts. Similar to fungal GEs, the bacterial enzymes are able to improve overall biomass deconstruction but also appear to have less strict substrate preferences for the uronic acid moiety. The structures of bacterial GEs reveal that they often have large inserts close to the active site, with implications for more extensive substrate interactions than the fungal GEs which have more open active sites. In this review, we highlight the recent work on GEs which has predominantly regarded bacterial enzymes, and discuss similarities and differences between bacterial and fungal enzymes in terms of the biochemical properties, diversity in sequence and modularity, and structural variations that have been discovered thus far in CE15.</p>","PeriodicalId":11812,"journal":{"name":"Essays in biochemistry","volume":"67 3","pages":"493-503"},"PeriodicalIF":6.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/8a/82/ebc-67-ebc20220155.PMC10154605.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9463758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Enzyme synergy for plant cell wall polysaccharide degradation.","authors":"Ahmed Khamassi, Claire Dumon","doi":"10.1042/EBC20220166","DOIUrl":"https://doi.org/10.1042/EBC20220166","url":null,"abstract":"<p><p>Valorizing plant cell wall, marine and algal polysaccharides is of utmost importance for the development of the circular bioeconomy. This is because polysaccharides are by far the most abundant organic molecules found in nature with complex chemical structures that require a large set of enzymes for their degradation. Microorganisms produce polysaccharide-specific enzymes that act in synergy when performing hydrolysis. Although discovered since decades enzyme synergy is still poorly understood at the molecular level and thus it is difficult to harness and optimize. In the last few years, more attention has been given to improve and characterize enzyme synergy for polysaccharide valorization. In this review, we summarize literature to provide an overview of the different type of synergy involving carbohydrate modifying enzymes and the recent advances in the field exemplified by plant cell-wall degradation.</p>","PeriodicalId":11812,"journal":{"name":"Essays in biochemistry","volume":"67 3","pages":"521-531"},"PeriodicalIF":6.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10080790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the impact of carbohydrate-binding modules (CBMs) in lytic polysaccharide monooxygenases (LPMOs).","authors":"Zarah Forsberg, Gaston Courtade","doi":"10.1042/EBC20220162","DOIUrl":"https://doi.org/10.1042/EBC20220162","url":null,"abstract":"<p><p>Lytic polysaccharide monooxygenases (LPMOs) have revolutionized our understanding of how enzymes degrade insoluble polysaccharides. Compared with the substantial knowledge developed on the structure and mode of action of the catalytic LPMO domains, the (multi)modularity of LPMOs has received less attention. The presence of other domains, in particular carbohydrate-binding modules (CBMs), tethered to LPMOs has profound implications for the catalytic performance of the full-length enzymes. In the last few years, studies on LPMO modularity have led to advancements in elucidating how CBMs, other domains, and linker regions influence LPMO structure and function. This mini review summarizes recent literature, with particular focus on comparative truncation studies, to provide an overview of the diversity in LPMO modularity and the functional implications of this diversity.</p>","PeriodicalId":11812,"journal":{"name":"Essays in biochemistry","volume":"67 3","pages":"561-574"},"PeriodicalIF":6.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10154629/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9408919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maria Louise Leth, Michael Jakob Pichler, Maher Abou Hachem
{"title":"Butyrate-producing colonic clostridia: picky glycan utilization specialists.","authors":"Maria Louise Leth, Michael Jakob Pichler, Maher Abou Hachem","doi":"10.1042/EBC20220125","DOIUrl":"https://doi.org/10.1042/EBC20220125","url":null,"abstract":"<p><p>Butyrate-producing human gut microbiota members are recognized for their strong association with a healthy immune-homeostasis and protection from inflammatory disorders and colorectal cancer. These effects are attributed to butyrate, the terminal electron sink of glycan fermentation by prevalent and abundant colonic Firmicutes from the Lachnospiraceae and Oscillospiraceae families. Remarkably, our insight into the glycan utilization mechanisms and preferences of butyrogenic Firmicutes remains very limited as compared with other gut symbionts, especially from the Bacteroides, Bifidobacterium, and Lactobacillus genera. Here, we summarize recent findings on the strategies that colonic butyrate producers have evolved to harvest energy from major dietary fibres, especially plant structural and storage glycans, such as resistant starch, xylans, and mannans. Besides dietary fibre, we also present the unexpected discovery of a conserved protein apparatus that confers the growth of butyrate producers on human milk oligosaccharides (HMOs), which are unique to mother's milk. The dual dietary fibre/HMO utilization machinery attests the adaptation of this group to both the infant and adult guts. These finding are discussed in relation to the early colonization of butyrogenic bacteria and the maturation of the microbiota during the transition from mother's milk to solid food. To date, the described butyrogenic Firmicutes are glycan utilization specialists that target only a few glycans in a highly competitive manner relying on co-regulated glycan utilization loci. We describe the common pillars of this machinery, highlighting butyrate producers as a source for discovery of biochemically and structurally novel carbohydrate active enzymes.</p>","PeriodicalId":11812,"journal":{"name":"Essays in biochemistry","volume":"67 3","pages":"415-428"},"PeriodicalIF":6.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9688388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}