1g0l
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CRYSTAL STRUCTURE OF T4 LYSOZYME MUTANT T152V
OverviewOverview
To investigate the structural and thermodynamic basis of the binding of, solvent at internal sites within proteins a number of mutations were, constructed in T4 lysozyme. Some of these were designed to introduce new, solvent-binding sites. Others were intended to displace solvent from, preexisting sites. In one case Val-149 was replaced with alanine, serine, cysteine, threonine, isoleucine, and glycine. Crystallographic analysis, shows that, with the exception of isoleucine, each of these substitutions, results in the binding of solvent at a polar site that is sterically, blocked in the wild-type enzyme. Mutations designed to perturb or displace, a solvent molecule present in the native enzyme included the replacement, of Thr-152 with alanine, serine, cysteine, valine, and isoleucine., Although the solvent molecule was moved in some cases by up to 1.7 A, in, no case was it completely removed from the folded protein. The results, suggest that hydrogen bonds from the protein to bound solvent are energy, neutral. The binding of solvent to internal sites within proteins also, appears to be energy neutral except insofar as the bound solvent may, prevent a loss of energy due to potential hydrogen bonding groups that, would otherwise be unsatisfied. The introduction of a solvent-binding site, appears to require not only a cavity to accommodate the water molecule but, also the presence of polar groups to help satisfy its hydrogen-bonding, potential. It may be easier to design a site to accommodate two or more, water molecules rather than one as the solvent molecules can then, hydrogen-bond to each other. For similar reasons it is often difficult to, design a point mutation that will displace a single solvent molecule from, the core of a protein.
About this StructureAbout this Structure
1G0L is a Single protein structure of sequence from Bacteriophage t4 with CL and HED as ligands. Active as Lysozyme, with EC number 3.2.1.17 Full crystallographic information is available from OCA.
ReferenceReference
Structural and thermodynamic analysis of the binding of solvent at internal sites in T4 lysozyme., Xu J, Baase WA, Quillin ML, Baldwin EP, Matthews BW, Protein Sci. 2001 May;10(5):1067-78. PMID:11316887
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