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1qtg is a 2 chain structure with sequence from Enterobacteria phage p22. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
A "switch" mutant of the Arc repressor homodimer was constructed by interchanging the sequence positions of a hydrophobic core residue, leucine 12, and an adjacent surface polar residue, asparagine 11, in each strand of an intersubunit beta sheet. The mutant protein adopts a fold in which each beta strand is replaced by a right-handed helix and side chains in this region undergo significant repacking. The observed structural changes allow the protein to maintain solvent exposure of polar side chains and optimal burial of hydrophobic side chains. These results suggest that new protein folds can evolve from existing folds without drastic or large-scale mutagenesis.
Evolution of a protein fold in vitro.,Cordes MH, Walsh NP, McKnight CJ, Sauer RT Science. 1999 Apr 9;284(5412):325-8. PMID:10195898[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑ Cordes MH, Walsh NP, McKnight CJ, Sauer RT. Evolution of a protein fold in vitro. Science. 1999 Apr 9;284(5412):325-8. PMID:10195898
