title: Characters of very ancient proteins.
abstract: Tracing the characters of very ancient proteins represents one of the biggest challenges in the study of origin of life. Although there are no primitive protein fossils remaining, the characters of very ancient proteins can be traced by molecular fossils embedded in modern proteins. In this paper, first the prior findings in this area are outlined and then a new strategy is proposed to address the intriguing issue. It is interesting to find that various molecular fossils and different protein datasets lead to similar conclusions on the features of very ancient proteins, which can be summarized as follows: (i) the architectures of very ancient proteins belong to the following folds: P-loop containing nucleoside triphosphate hydrolases (c.37), TIM beta/alpha-barrel (c.1), NAD(P)-binding Rossmann-fold domains (c.2), Ferredoxin-like (d.58), Flavodoxin-like (c.23) and Ribonuclease H-like motif (c.55); (ii) the functions of very ancient proteins are related to the metabolisms of purine, pyrimidine, porphyrin, chlorophyll and carbohydrates; (iii) a certain part of very ancient proteins need cofactors (such as ATP, NADH or NADPH) to work normally.
authors: Shandong Provincial Research Center for Bioinformatic Engineering and Technique, Center for Advanced Study, Shandong University of Technology, Zibo 255049, PR China.
authors: Bin-Guang
authors: BG
authors: Ma
authors: Lei
authors: L
authors: Chen
authors: Hong-Fang
authors: HF
authors: Ji
authors: Zhong-Hua
authors: ZH
authors: Chen
authors: Fu-Rong
authors: FR
authors: Yang
authors: Ling
authors: L
authors: Wang
authors: Ge
authors: G
authors: Qu
authors: Ying-Ying
authors: YY
authors: Jiang
authors: Cong
authors: C
authors: Ji
authors: Hong-Yu
authors: HY
authors: Zhang
mesh_terms: D019143:Evolution, Molecular; D014644:Genetic Variation / Q000235:genetics*; D008957:Models, Genetic; D000069497:Origin of Life; D020543:Proteome / Q000737:chemistry* / Q000235:genetics*; D013997:Time Factors
chemical_list: D020543:Proteome