Phylogenetic analysis and structural studies of heteromeric acetyl-CoA carboxylase from the oleaginous Amazonian microalgae Ankistrodesmus sp.: Insights into the BC and BCCP subunits
Andry Mercedes Mavila , Jhon Antoni Vargas , Eloy Condori , Erick Giancarlo Suclupe Farro , Adriano Alves Furtado , Josué Manuel López , Silvia Lucila Gonzalez , Humberto D’Muniz Pereira , Jorge Luis Marapara , Roger Ruiz Paredes , Marianela Cobos , Juan C. Castro , Richard Charles Garratt , Diego Antonio Leonardo
{"title":"Phylogenetic analysis and structural studies of heteromeric acetyl-CoA carboxylase from the oleaginous Amazonian microalgae Ankistrodesmus sp.: Insights into the BC and BCCP subunits","authors":"Andry Mercedes Mavila , Jhon Antoni Vargas , Eloy Condori , Erick Giancarlo Suclupe Farro , Adriano Alves Furtado , Josué Manuel López , Silvia Lucila Gonzalez , Humberto D’Muniz Pereira , Jorge Luis Marapara , Roger Ruiz Paredes , Marianela Cobos , Juan C. Castro , Richard Charles Garratt , Diego Antonio Leonardo","doi":"10.1016/j.jsb.2025.108200","DOIUrl":null,"url":null,"abstract":"<div><div>Acetyl-CoA carboxylase (ACC) is an essential enzyme in fatty acid biosynthesis that catalyzes the formation of malonyl-CoA from acetyl-CoA. While structural studies on ACC components have largely focused on prokaryotes and higher plants, the assembly and molecular adaptations of ACC in microalgae remain underexplored. This study aimed to fill this gap by providing the first structural and evolutionary characterization of both biotin carboxylase (BC) and biotin carboxyl carrier protein (BCCP) from a microalga (<em>Ankistrodesmus</em> sp.<em>)</em>. Phylogenetic analysis revealed distinct evolutionary trajectories for BC and BCCP, with BC forming a chlorophyte-specific clade closely related to other oleaginous species, while BCCP displayed two distinct isoforms within green algae, resulting from gene duplication. The crystallographic structure of BC was solved in its apo (1.75 Å) and ADP-Mg<sup>2+</sup>-bound (1.90 Å) states, revealing conserved conformational changes associated with cofactor binding. BCCP from <em>Ankistrodesmus</em> sp. displayed a unique QLGTF/H motif instead of the canonical AMKXM biotinylation motif, suggesting loss of biotinylation capacity. However, the presence of three additional lysines in the protruding thumb loop, with Lys95 as a candidate for biotin attachment, indicates potential compensatory adaptations. SEC-MALS and pull-down assays confirmed the formation of a stable 1:1 BC-BCCP complex, and circular dichroism showed increased thermal stability of the complex, supporting its structural stability. This study highlights unique structural adaptations in <em>Ankistrodesmus</em> sp. ACC, emphasizing the evolutionary plasticity of BC and BCCP. These insights provide a foundation for future investigations into ACC regulation in photosynthetic organisms and offer potential biotechnological applications for optimizing lipid production in microalgae.</div></div>","PeriodicalId":17074,"journal":{"name":"Journal of structural biology","volume":"217 2","pages":"Article 108200"},"PeriodicalIF":3.0000,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of structural biology","FirstCategoryId":"99","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1047847725000358","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Acetyl-CoA carboxylase (ACC) is an essential enzyme in fatty acid biosynthesis that catalyzes the formation of malonyl-CoA from acetyl-CoA. While structural studies on ACC components have largely focused on prokaryotes and higher plants, the assembly and molecular adaptations of ACC in microalgae remain underexplored. This study aimed to fill this gap by providing the first structural and evolutionary characterization of both biotin carboxylase (BC) and biotin carboxyl carrier protein (BCCP) from a microalga (Ankistrodesmus sp.). Phylogenetic analysis revealed distinct evolutionary trajectories for BC and BCCP, with BC forming a chlorophyte-specific clade closely related to other oleaginous species, while BCCP displayed two distinct isoforms within green algae, resulting from gene duplication. The crystallographic structure of BC was solved in its apo (1.75 Å) and ADP-Mg2+-bound (1.90 Å) states, revealing conserved conformational changes associated with cofactor binding. BCCP from Ankistrodesmus sp. displayed a unique QLGTF/H motif instead of the canonical AMKXM biotinylation motif, suggesting loss of biotinylation capacity. However, the presence of three additional lysines in the protruding thumb loop, with Lys95 as a candidate for biotin attachment, indicates potential compensatory adaptations. SEC-MALS and pull-down assays confirmed the formation of a stable 1:1 BC-BCCP complex, and circular dichroism showed increased thermal stability of the complex, supporting its structural stability. This study highlights unique structural adaptations in Ankistrodesmus sp. ACC, emphasizing the evolutionary plasticity of BC and BCCP. These insights provide a foundation for future investigations into ACC regulation in photosynthetic organisms and offer potential biotechnological applications for optimizing lipid production in microalgae.
期刊介绍:
Journal of Structural Biology (JSB) has an open access mirror journal, the Journal of Structural Biology: X (JSBX), sharing the same aims and scope, editorial team, submission system and rigorous peer review. Since both journals share the same editorial system, you may submit your manuscript via either journal homepage. You will be prompted during submission (and revision) to choose in which to publish your article. The editors and reviewers are not aware of the choice you made until the article has been published online. JSB and JSBX publish papers dealing with the structural analysis of living material at every level of organization by all methods that lead to an understanding of biological function in terms of molecular and supermolecular structure.
Techniques covered include:
• Light microscopy including confocal microscopy
• All types of electron microscopy
• X-ray diffraction
• Nuclear magnetic resonance
• Scanning force microscopy, scanning probe microscopy, and tunneling microscopy
• Digital image processing
• Computational insights into structure