Download MendeleyMg2+ activation of Escherichia coli inorganic pyrophosphatase.
Avaeva, S.M., Rodina, E.V., Kurilova, S.A., Nazarova, T.I., Vorobyeva, N.N., Harutyunyan, E.H., VYu, Oganessyan(1995) FEBS Lett 377: 44-46
- PubMed: 8543015
- DOI: https://doi.org/10.1016/0014-5793(95)01310-5
- Primary Citation of Related Structures:
1INO - PubMed Abstract:
Further refinement of X-ray data on Escherichia coli inorganic pyrophosphatase [Oganessyan et al. (1994) FEBS Lett. 348, 301-304] to 2.2 A 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.
Organizational Affiliation:
A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russian Federation.
