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Requirements for perpendicular helix pairing
Author(s) -
Beasley James R.,
Pielak Gary J.
Publication year - 1996
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(199609)26:1<95::aid-prot9>3.0.co;2-f
Subject(s) - saccharomyces cerevisiae , mutagenesis , yeast , genetics , cytochrome , mutation , amino acid , cytochrome c , biology , helix (gastropod) , stereochemistry , chemistry , biochemistry , gene , mitochondrion , enzyme , ecology , snail
Cassette mutagenesis was used to produce a library of mutations at the interface of the N‐ and C‐terminal helices of Saccharomyces cerevisiae iso‐1‐cytochrome c . The library is random and comprises >98% mutations. Over 11,000 candidates were assayed for function by selecting for the ability of yeast, with the mutated gene as their sole cytochrome c source, to grow on nonfermentable carbon sources. We estimate that ≈0.5% of the 160,000 total amino acid combinations at these four residues result in a functional cytochrome c . Significant correlations are found between the phenotype of yeast harboring the alleles and both the Dayhoff mutation matrix and transfer free energies (cyclohexane‐to‐water and n ‐octanol‐to‐water). Similar correlations are observed with respect to growth rate. Finally, sequences that are consistent with function follow a binary amino acid pattern. © 1996 Wiley‐Liss, Inc.