Our globin census update allows us to refine our vision of globin origin, evolution, and structure to function relationship in the context of the currently accepted tree of life. The modern globin domain originates as a single domain, three-over-three α-helical folded structure before the diversification of the kingdoms of life (Bacteria, Archaea, Eukarya). Together with the diversification of prokaryotes, three monophyletic globin families (M, S, and T) emerged, most likely in Proteobacteria and Actinobacteria, displaying specific sequence and structural features, and spread by vertical and horizontal gene transfer, most probably already present in the last universal common ancestor (LUCA). Non-globin domains were added, and eventually lost again, creating multi-domain structures in key branches of M- (FHb and Adgb) and the vast majority of S globins, which with their coevolved multi-domain architectures, have predominantly “sensor” functions. Single domain T-family globins diverged into four major groups and most likely display functions related to reactive nitrogen and oxygen species (RNOS) chemistry, as well as oxygen storage/transport which drives the evolution of its major branches with their characteristic key distal residues (B10, E11, E7, and G8). M-family evolution also lead to distinctive major types (FHb and Fgb, Ngb, Adgb, GbX vertebrate Gbs), and shows the shift from high oxygen affinity controlled by TyrB10-Gln/AsnE11 likely related to RNOS chemistry in microorganisms, to a moderate oxygen affinity storage/transport function controlled by hydrophobic B10/E11–HisE7 in multicellular animals.

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球蛋白系统发育、进化和功能，最新更新

我们的球蛋白普查更新使我们能够在当前公认的生命树背景下完善对球蛋白起源、进化和结构与功能关系的看法。现代球蛋白结构域起源于生命王国（细菌、古细菌、真核生物）多样化之前的单一结构域、三上三α螺旋折叠结构。随着原核生物的多样化，出现了三个单系球蛋白家族（M、S 和 T），最有可能出现在变形菌门和放线菌门中，表现出特定的序列和结构特征，并通过垂直和水平基因转移传播，最有可能已经存在于原核生物中。最后的普遍共同祖先（LUCA）。添加了非球蛋白结构域，但最终再次丢失，在 M-（FHb 和 Adgb）和绝大多数 S 球蛋白的关键分支中创建了多结构域结构，这些球蛋白及其共同进化的多结构域结构主要具有“传感器”功能。单域 T 家族球蛋白分为四个主要组，最有可能表现出与活性氮和氧物种 (RNOS) 化学以及氧储存/运输相关的功能，这驱动其主要分支及其特征性关键远端残基的进化。 B10、E11、E7 和 G8）。M 家族进化还导致了独特的主要类型（FHb 和 Fgb、Ngb、Adgb、GbX 脊椎动物 Gbs），并显示出从可能与微生物中的 RNOS 化学相关的 TyrB10-Gln/AsnE11 控制的高氧亲和力转变为中等氧亲和力。多细胞动物中疏水性 B10/E11–HisE7 控制氧亲和力储存/运输功能。