1urb
From Proteopedia
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ALKALINE PHOSPHATASE (N51MG)
Overview
In each subunit of the homodimeric enzyme Escherichia coli alkaline, phosphatase, two of the three metal cofactors Zn2+ and Mg2+, are bound by, an aspartate side-chain at position 51. Using site-specific mutagenesis, Asp51 was mutated both to alanine and to asparagine to produce the D51A, and D51N enzymes, respectively. Over the range of pH values examined, the, D51A enzyme did not catalyze phosphate ester hydrolysis above non-enzymic, levels and was not activated by the addition of millimolar excess Zn2+ or, Mg2+. Replacement of Asp51 by asparagine, however, resulted in a mutant, enzyme with reduced activity and a higher pH optimum, compared with the, wild-type enzyme. At pH 8.0 the D51N enzyme showed about 1% of the, activity of the wild-type enzyme, and as the pH was raised to 9.2, ... [(full description)]
About this Structure
1URB is a [Single protein] structure of sequence from [Escherichia coli] with ZN, MG and PO4 as [ligands]. Active as [[1]], with EC number [3.1.3.1]. Full crystallographic information is available from [OCA].
Reference
Kinetic and structural consequences of replacing the aspartate bridge by asparagine in the catalytic metal triad of Escherichia coli alkaline phosphatase., Tibbitts TT, Murphy JE, Kantrowitz ER, J Mol Biol. 1996 Apr 5;257(3):700-15. PMID:8648634
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