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On the evolution of alternate core packing in eightfold β/α‐barrels
Author(s) -
Raine Andrew R.C.,
Scrutton Nigel S.,
Mathews F. Scott
Publication year - 1994
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560031028
Subject(s) - barrel (horology) , core (optical fiber) , side chain , convergent evolution , protein structure , biology , crystallography , evolutionary biology , chemistry , stereochemistry , biophysics , genetics , phylogenetic tree , biochemistry , computer science , gene , materials science , organic chemistry , composite material , polymer , telecommunications
Two sequence‐related subfamilies of flavin‐binding β/α‐barrels have been identified (the type I and type II proteins) that differ in the nature of residue packing in the core of the barrel domain. Similar observed differences in the packing of internal amino acid side chains in β/α‐barrels have previously been used to argue that these domains have evolved convergently toward a stable structural framework. Using structural alignments of flavin‐binding barrel proteins, we demonstrate that simple genetic alterations may be responsible for switching the nature of side‐chain packing observed in β/α‐barrels. The implication is that the 2 structural classes of β/α‐barrel cores can arise divergently from an ancestral barrel framework and that convergent evolution to a stable fold need not be invoked to account for the emergence of 2 classes of β/α‐barrel core.