{"title":"Mn(II)和Fe(II)阳离子与光系统II高亲和力Mn结合位点的竞争相互作用:进化方面的研究。","authors":"E R Lovyagina, B К Semin","doi":"10.1007/s11084-022-09625-8","DOIUrl":null,"url":null,"abstract":"<p><p>The evolutionary origin of the oxygen-evolving complex (OEC) in the photosystem II (PSII) is still unclear, as is the nature of electron source for the photosystem before the OEC had appeared. Johnson et al. (in PNAS 110:11238, 2013) speculated that Mn(II) cations were the source of electrons for transitional photosystems. However, Archean oceans also contained Fe(II) cations at concentrations comparable or higher than that of Mn(II). Fe(II) cations can bind to the high-affinity (НА) Mn-binding site in the OEC (Semin et al. in Biochemistry 41:5854, 2002). Now we have investigated the competitive interaction of Mn(II) and Fe(II) cations with the HA site in the Mn-depleted PSII membranes (PSII[-Mn]). Fe cations, oxidized under illumination, bind strongly to the HA site and, thus, prevent the interaction of Mn(II) with this site. If the Mn(II) and Fe(II) cations, at relatively equal concentration, are simultaneously present in the buffer, together with PSII(-Mn) membranes, there is competition between these two cations for the binding site, which manifests itself in partial inhibition of the Mn(II) oxidation and the blocking of the HA site by Fe(II) cations. If the concentration of Fe(II) cations is several times higher than the concentration of Mn(II), the HA site is completely blocked and the oxidation of Mn(II) cations is inhibited; under saturating light, the effectiveness of this inhibitory effect increases. This may be due to the generation of H<sub>2</sub>O<sub>2</sub> on the acceptor side of the photosystem, which significantly accelerates the rate of the turnover reaction of Mn(II) on the HA site.</p>","PeriodicalId":19614,"journal":{"name":"Origins of Life and Evolution of Biospheres","volume":null,"pages":null},"PeriodicalIF":1.9000,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Competitive interaction of Mn(II) and Fe(II) cations with the high-affinity Mn-binding site of the photosystem II: evolutionary aspect.\",\"authors\":\"E R Lovyagina, B К Semin\",\"doi\":\"10.1007/s11084-022-09625-8\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>The evolutionary origin of the oxygen-evolving complex (OEC) in the photosystem II (PSII) is still unclear, as is the nature of electron source for the photosystem before the OEC had appeared. Johnson et al. (in PNAS 110:11238, 2013) speculated that Mn(II) cations were the source of electrons for transitional photosystems. However, Archean oceans also contained Fe(II) cations at concentrations comparable or higher than that of Mn(II). Fe(II) cations can bind to the high-affinity (НА) Mn-binding site in the OEC (Semin et al. in Biochemistry 41:5854, 2002). Now we have investigated the competitive interaction of Mn(II) and Fe(II) cations with the HA site in the Mn-depleted PSII membranes (PSII[-Mn]). Fe cations, oxidized under illumination, bind strongly to the HA site and, thus, prevent the interaction of Mn(II) with this site. If the Mn(II) and Fe(II) cations, at relatively equal concentration, are simultaneously present in the buffer, together with PSII(-Mn) membranes, there is competition between these two cations for the binding site, which manifests itself in partial inhibition of the Mn(II) oxidation and the blocking of the HA site by Fe(II) cations. If the concentration of Fe(II) cations is several times higher than the concentration of Mn(II), the HA site is completely blocked and the oxidation of Mn(II) cations is inhibited; under saturating light, the effectiveness of this inhibitory effect increases. This may be due to the generation of H<sub>2</sub>O<sub>2</sub> on the acceptor side of the photosystem, which significantly accelerates the rate of the turnover reaction of Mn(II) on the HA site.</p>\",\"PeriodicalId\":19614,\"journal\":{\"name\":\"Origins of Life and Evolution of Biospheres\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.9000,\"publicationDate\":\"2022-09-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Origins of Life and Evolution of Biospheres\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.1007/s11084-022-09625-8\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"2022/7/7 0:00:00\",\"PubModel\":\"Epub\",\"JCR\":\"Q2\",\"JCRName\":\"BIOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Origins of Life and Evolution of Biospheres","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1007/s11084-022-09625-8","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2022/7/7 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"BIOLOGY","Score":null,"Total":0}
引用次数: 0
摘要
光系统II (PSII)中氧进化复合体(OEC)的进化起源尚不清楚，在OEC出现之前光系统的电子源性质也不清楚。Johnson等人(发表在PNAS 110:11238, 2013)推测Mn(II)阳离子是过渡光系统的电子来源。然而，太古宙海洋也含有Fe(II)阳离子，其浓度与Mn(II)相当或更高。Fe(II)阳离子可以结合到OEC中高亲和力的mn结合位点(НА) (Semin et al. in Biochemistry 41:58 . 54, 2002)。现在，我们研究了Mn(II)和Fe(II)阳离子与贫Mn PSII膜(PSII[-Mn])中HA位点的竞争相互作用。铁离子在光照下被氧化，与HA位点强烈结合，从而阻止Mn(II)与该位点的相互作用。如果Mn(II)和Fe(II)阳离子以相对相等的浓度同时存在于缓冲液中，并与PSII(-Mn)膜一起存在，则这两个阳离子之间存在对结合位点的竞争，表现为部分抑制Mn(II)氧化和Fe(II)阳离子阻断HA位点。如果Fe(II)阳离子浓度比Mn(II)浓度高几倍，则HA位点被完全阻断，Mn(II)阳离子的氧化被抑制;在饱和光下，这种抑制作用的有效性增加。这可能是由于在光系统的受体侧产生H2O2，这显著加快了Mn(II)在HA位点上的周转反应速度。
Competitive interaction of Mn(II) and Fe(II) cations with the high-affinity Mn-binding site of the photosystem II: evolutionary aspect.
The evolutionary origin of the oxygen-evolving complex (OEC) in the photosystem II (PSII) is still unclear, as is the nature of electron source for the photosystem before the OEC had appeared. Johnson et al. (in PNAS 110:11238, 2013) speculated that Mn(II) cations were the source of electrons for transitional photosystems. However, Archean oceans also contained Fe(II) cations at concentrations comparable or higher than that of Mn(II). Fe(II) cations can bind to the high-affinity (НА) Mn-binding site in the OEC (Semin et al. in Biochemistry 41:5854, 2002). Now we have investigated the competitive interaction of Mn(II) and Fe(II) cations with the HA site in the Mn-depleted PSII membranes (PSII[-Mn]). Fe cations, oxidized under illumination, bind strongly to the HA site and, thus, prevent the interaction of Mn(II) with this site. If the Mn(II) and Fe(II) cations, at relatively equal concentration, are simultaneously present in the buffer, together with PSII(-Mn) membranes, there is competition between these two cations for the binding site, which manifests itself in partial inhibition of the Mn(II) oxidation and the blocking of the HA site by Fe(II) cations. If the concentration of Fe(II) cations is several times higher than the concentration of Mn(II), the HA site is completely blocked and the oxidation of Mn(II) cations is inhibited; under saturating light, the effectiveness of this inhibitory effect increases. This may be due to the generation of H2O2 on the acceptor side of the photosystem, which significantly accelerates the rate of the turnover reaction of Mn(II) on the HA site.
期刊介绍：
The subject of the origin and early evolution of life is an inseparable part of the general discipline of Astrobiology. The journal Origins of Life and Evolution of Biospheres places special importance on the interconnection as well as the interdisciplinary nature of these fields, as is reflected in its subject coverage. While any scientific study which contributes to our understanding of the origins, evolution and distribution of life in the Universe is suitable for inclusion in the journal, some examples of important areas of interest are: prebiotic chemistry and the nature of Earth''s early environment, self-replicating and self-organizing systems, the theory of the RNA world and of other possible precursor systems, and the problem of the origin of the genetic code. Early evolution of life - as revealed by such techniques as the elucidation of biochemical pathways, molecular phylogeny, the study of Precambrian sediments and fossils and of major innovations in microbial evolution - forms a second focus. As a larger and more general context for these areas, Astrobiology refers to the origin and evolution of life in a cosmic setting, and includes interstellar chemistry, planetary atmospheres and habitable zones, the organic chemistry of comets, meteorites, asteroids and other small bodies, biological adaptation to extreme environments, life detection and related areas. Experimental papers, theoretical articles and authorative literature reviews are all appropriate forms for submission to the journal. In the coming years, Astrobiology will play an even greater role in defining the journal''s coverage and keeping Origins of Life and Evolution of Biospheres well-placed in this growing interdisciplinary field.
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