Histidine modification and mutagenesis point to the involvement of a large conformational change in the mechanism of action of phage lambda lysozyme.
Phage lambda lysozyme (lambdaL) is structurally related to other known lysozymes but its mechanism of action is different from the classical lysozyme mechanism, acting as a transglycosidase rather than a hydrolase. As two conformations have been revealed by the crystal structure, we investigated the effect of mutating and modifying a histidine located near to or far from the active site in the respective closed and open conformations. Whereas its asparagine mutation has little or no effect on activity, its N-carbethoxylation inactivates the enzyme. This provide further evidence for the involvement of the closed conformation and for the need of conformational mobility in lambdaL function.
Evrard
C
C
Université Catholique de Louvain, Laboratoire de Biochimie Physique et des Biopolymères, Place L. Pasteur 1-1B, B-1348, Louvain-la-Neuve, Belgium.
Fastrez
J
J
Soumillion
P
P
D010582:Bacteriophage lambda / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects / Q000235:genetics; D004795:Enzyme Stability / Q000187:drug effects / Q000235:genetics; D006639:Histidine / Q000235:genetics* / Q000378:metabolism*; D008958:Models, Molecular; D009113:Muramidase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed / Q000235:genetics*; D011487:Protein Conformation / Q000187:drug effects; D014764:Viral Proteins / Q000235:genetics
D014764:Viral Proteins; D006639:Histidine; D009113:Muramidase; D004047:Diethyl Pyrocarbonate