1lba: Difference between revisions

[[Image:1lba.gif|left|200px]]<br /><applet load="1lba" size="350" color="white" frame="true" align="right" spinBox="true"  

The lysozyme of bacteriophage T7 is a bifunctional protein that cuts amide bonds in the bacterial cell wall and binds to and inhibits transcription by T7 RNA polymerase. The structure of a mutant T7 lysozyme has been determined by x-ray crystallography and refined at 2.2-A resolution. The protein folds into an alpha/beta-sheet structure that has a prominent cleft. A zinc atom is located in the cleft, bound directly to three amino acids and, through a water molecule, to a fourth. Zinc is required for amidase activity but not for inhibition of T7 RNA polymerase. Alignment of the zinc ligands of T7 lysozyme with those of carboxypeptidase A and thermolysin suggests structural similarity among the catalytic sites for the amidase and these zinc proteases. Mutational analysis identified presumed catalytic residues for amidase activity within the cleft and a surface that appears to be the site of binding to T7 RNA polymerase. Binding of T7 RNA polymerase inhibits amidase activity.

1LBA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t7 Bacteriophage t7] with <scene name='pdbligand=ZN:'>ZN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/N-acetylmuramoyl-L-alanine_amidase N-acetylmuramoyl-L-alanine amidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.1.28 3.5.1.28] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LBA OCA].  

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