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PDBsum entry 1hep
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Hydrolase(o-glycosyl)
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PDB id
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1hep
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References listed in PDB file
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Key reference
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Title
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Structural and thermodynamic analysis of compensating mutations within the core of chicken egg white lysozyme.
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Authors
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K.P.Wilson,
B.A.Malcolm,
B.W.Matthews.
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Ref.
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J Biol Chem, 1992,
267,
10842-10849.
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PubMed id
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Abstract
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High resolution crystal structures have been determined for six chicken-type
lysozymes that were constructed to investigate putative intermediates in the
evolution of the lysozymes of modern game birds (Malcolm, B. A., Wilson, K. P.,
Matthews, B. W., Kirsch, J. F., and Wilson, A. C. (1990) Nature 345, 86-89). The
amino acid replacements include Thr-40----Ser, Ile-55----Val, and Ser-91----Thr,
as well as combinations of these substitutions. Residues 40, 55, and 91 are
buried within the core of chicken lysozyme. The replacements therefore involve
the insertion and/or removal of methyl groups from the protein interior. The
mutant proteins have normal activities, and their thermal stabilities span a
range of 7 degrees C, with some variants more stable and some less stable than
the naturally occurring forms. Comparison of the crystal structures shows the
overall structures to be very similar, but there are differences in the packing
of side chains in the region of the replacements. The x-ray coordinates were
used to evaluate the repacking of side chains in the protein interior and to
attempt to evaluate the contributions of the different energetic interactions
toward the overall stability of each variant. The results illustrate how
proteins can compensate for potentially destabilizing substitutions in different
ways and underscore the importance of high resolution structural data if changes
in protein thermostability due to changes in protein sequence are to be
understood. The findings also suggest that protein stability can be increased by
mutations that lower strain in the protein interior while maintaining total
buried hydrophobic surface area.
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Secondary reference #1
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Title
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Ancestral lysozymes reconstructed, Neutrality tested, And thermostability linked to hydrocarbon packing.
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Authors
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B.A.Malcolm,
K.P.Wilson,
B.W.Matthews,
J.F.Kirsch,
A.C.Wilson.
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Ref.
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Nature, 1990,
345,
86-89.
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PubMed id
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