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Multifunctional enzymes and evolution of biosynthetic pathways: Retro‐evolution by jumps
Author(s) -
Roy Siddhartha
Publication year - 1999
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/(sici)1097-0134(19991101)37:2<303::aid-prot15>3.0.co;2-6
Subject(s) - extant taxon , biology , enzyme , most recent common ancestor , metabolic pathway , directed evolution , mechanism (biology) , gene , sequence (biology) , evolutionary biology , gene duplication , genetics , phylogenetics , biochemistry , philosophy , epistemology , mutant
A likely scenario of evolution of biosynthetic pathways is believed to have occurred by retro‐evolution through recruitment of existing enzymes rather than generation of de novo classes. It had been proposed that such retro‐evolution occurred in steps as a response to depletion of an essential metabolite and availability of another related substance in the environment. In this article, I argue that because of instability of many such extant intermediates, it is unlikely that retro‐evolution had occurred in steps. I further propose that such evolution in many cases has taken place by jumps, i.e., by recruitment of a multifunctional enzyme capable of catalyzing several steps at a time, albeit inefficiently. I further speculate that in some cases one primordial multienzyme may have catalyzed the whole sequence of reaction of a biosynthetic pathway, i.e., the pathway may have evolved by a single leap. Gene duplications and further evolution to more efficient enzymes led to extant pathways. Such a mechanism predicts that some or all enzymes of a pathway must have descended from a common ancestor. Sequence and structural homologies among extant enzymes of a biosynthetic pathway have been examined. Proteins 1999;37:303–309. ©1999 Wiley‐Liss, Inc.