1l96

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spinqualitylabelsall models 1l96, resolution 2.0Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

STRUCTURE OF A HINGE-BENDING BACTERIOPHAGE T4 LYSOZYME MUTANT, ILE3-> PRO

Overview

The mutant T4 phage lysozyme in which isoleucine 3 is replaced by proline, (I3P) crystallizes in an orthorhombic form with two independent molecules, in the asymmetric unit. Relative to wild-type lysozyme, which crystallizes, in a trigonal form, the two I3P molecules undergo large hinge-bending, displacements with the alignments of the amino-terminal and, carboxy-terminal domains changed by 28.9 degrees and 32.9 degrees, respectively. The introduction of the mutation, together with the, hinge-bending displacement, is associated with repacking of the, side-chains of Phe4, Phe67 and Phe104. These aromatic residues are, clustered close to the site of the mutation and are at the junction, between the amino and carboxyl-terminal domains. As a result of this, structural rearrangement the side-chain of Phe4 moves from a relatively, solvent-exposed conformation to one that is largely buried. Mutant I3P, also crystallizes in the same trigonal form as wild-type and, in this, case, the observed structural changes are restricted to the immediate, vicinity of the replacement. The main change is a shift of 0.3 to 0.5 A in, the backbone of residues 1 to 5. The ability to crystallize I3P under, similar conditions but in substantially different conformations suggests, that the molecule undergoes large-scale hinge-bending displacements in, solution. It is also likely that these conformational excursions are, associated with repacking at the junction of the N-terminal and C-terminal, domains. On the other hand, the analysis is complicated by possible, effects of crystal packing. The different I3P crystal structures show, substantial differences in the binding of solvent, both at the site of the, Ile3-->Pro replacement and at other internal sites.

About this Structure

1L96 is a Single protein structure of sequence from Bacteriophage t4 with CL and BME as ligands. Active as Lysozyme, with EC number 3.2.1.17 Full crystallographic information is available from OCA.

Reference

Structure of a hinge-bending bacteriophage T4 lysozyme mutant, Ile3-->Pro., Dixon MM, Nicholson H, Shewchuk L, Baase WA, Matthews BW, J Mol Biol. 1992 Oct 5;227(3):917-33. PMID:1404394

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