期刊论文详细信息
FEBS Letters
Mg2+ activation of Escherichia coli inorganic pyrophosphatase
Avaeva, Svetlana M.3  Kurilova, Svetlana A.3  Nazarova, Tatjana I.3  Oganessyan, Vaheh Yu.1  Harutyunyan, Emil H.1  Rodina, Elena V.3  Vorobyeva, Natalja N.2 
[1] Institute of Crystallography, Russian Academy of Science, Moscow, Russian Federation;Department of Chemistry, Moscow State University, Moscow 119899, Russian Federation;A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Vorobyevy Gory, Moscow 119899, Russian Federation
关键词: Inorganic pyrophosphatase;    Tyrosine;    Mg2+ binding;    Differential spectrophotometry;    X-ray analysis;   
DOI  :  10.1016/0014-5793(95)01310-5
学科分类:生物化学/生物物理
来源: John Wiley & Sons Ltd.
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【 摘 要 】

Further refinement of X-ray data on Escherichia coli inorganic pyrophosphatase [Oganessyan et al. (1994) FEBS Lett. 348, 301–304] to 2.2 Å reveals a system of noncovalent interactions involving Tyr55 and Tyr141 in the active site. The pKa for one of the eight Tyr residues in wild-type pyrophosphatase is as low as 9.1 and further decreases to 8.1 upon Mg2+ binding, generating characteristic changes in the absorption spectrum. These effects are lost in a Y55F but not in a Y141F variant. It is suggested that the lower-affinity site for Mg2+ in the enzyme is formed by Tyr55 and Asp70, which are in close proximity in the apo-enzyme structure.

【 授权许可】

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