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Title
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A test of the "jigsaw puzzle" model for protein folding by multiple methionine substitutions within the core of T4 lysozyme.
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Authors
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N.C.Gassner,
W.A.Baase,
B.W.Matthews.
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Ref.
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Proc Natl Acad Sci U S A, 1996,
93,
12155-12158.
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PubMed id
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Abstract
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To test whether the structure of a protein is determined in a manner akin to the
assembly of a jigsaw puzzle, up to 10 adjacent residues within the core of T4
lysozyme were replaced by methionine. Such variants are active and fold
cooperatively with progressively reduced stability. The structure of a
seven-methionine variant has been shown, crystallographically, to be similar to
wild type and to maintain a well ordered core. The interaction between the core
residues is, therefore, not strictly comparable with the precise spatial
complementarity of the pieces of a jigsaw puzzle. Rather, a certain amount of
give and take in forming the core structure is permitted. A simplified
hydrophobic core sequence, imposed without genetic selection or computer-based
design, is sufficient to retain native properties in a globular protein.
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