2a59: Difference between revisions

[[Image:2a59.gif|left|200px]]<br /><applet load="2a59" size="350" color="white" frame="true" align="right" spinBox="true"  

The amino acid residue tryptophan 27 of 6,7-dimethyl-8-ribityllumazine synthase of the yeast Schizosaccharomyces pombe was replaced by tyrosine. The structures of the W27Y mutant protein in complex with riboflavin, the substrate analogue 5-nitroso-6-ribitylamino-2,4(1H,3H)-pyrimidinedione, and the product analogue 6-carboxyethyl-7-oxo-8-ribityllumazine, were determined by X-ray crystallography at resolutions of 2.7-2.8 A. Whereas the indole system of W27 forms a coplanar pi-complex with riboflavin, the corresponding phenyl ring in the W27Y mutant establishes only peripheral contact with the heterocyclic ring system of the bound riboflavin. These findings provide an explanation for the absence of the long wavelength shift in optical absorption spectra of riboflavin bound to the mutant enzyme. The structures of the mutants are important tools for the interpretation of the unusual physical properties of riboflavin in complex with lumazine synthase.

2A59 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Schizosaccharomyces_pombe Schizosaccharomyces pombe] with <scene name='pdbligand=PO4:'>PO4</scene> and <scene name='pdbligand=LMZ:'>LMZ</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Riboflavin_synthase Riboflavin synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.5.1.9 2.5.1.9] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2A59 OCA].  

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