Structure of a hinge-bending bacteriophage T4 lysozyme mutant, Ile3-->Pro.

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