2hm4
From Proteopedia
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Nematocyst Outer Wall Antigen, NW1 K21P
Overview
Protein structures cluster into families of folds that can result from, extremely different amino acid sequences [1]. Because the enormous amount, of genetic information generates a limited number of protein folds [2], a, particular domain structure often assumes numerous functions. How new, protein structures and new functions evolve under these limitations, remains elusive. Molecular evolution may be driven by the ability of, biomacromolecules to adopt multiple conformations as a bridge between, different folds [3-6]. This could allow proteins to explore new structures, and new tasks while part of the structural ensemble retains the initial, conformation and function as a safeguard [7]. Here we show that a global, structural switch can arise from single amino acid changes in, cysteine-rich domains (CRD) of cnidarian nematocyst proteins. The ability, of these CRDs to form two structures with different disulfide patterns, from an identical cysteine pattern is distinctive [8]. By applying a, structure-based mutagenesis approach, we demonstrate that a cysteine-rich, domain can interconvert between two natively occurring domain structures, via a bridge state containing both structures. Comparing cnidarian CRD, sequences leads us to believe that the mutations we introduced to, stabilize each structure reflect the birth of new protein folds in, evolution.
About this Structure
2HM4 is a Single protein structure of sequence from Hydra vulgaris. Full crystallographic information is available from OCA.
Reference
Continuous molecular evolution of protein-domain structures by single amino acid changes., Meier S, Jensen PR, David CN, Chapman J, Holstein TW, Grzesiek S, Ozbek S, Curr Biol. 2007 Jan 23;17(2):173-8. PMID:17240343
Page seeded by OCA on Tue Jan 29 20:23:47 2008
