Genetic engineering of Escherichia coli inorganic pyrophosphatase Tyr55 and Tyr141 are important for the structural integrity - UTU Research Portal

Genetic engineering of Escherichia coli inorganic pyrophosphatase
Tyr55 and Tyr141 are important for the structural integrity

: LAHTI R, SALMINEN T, LATONEN S, HEIKINHEIMO P, POHJANOKSA K, HEINONEN J

Publisher: SPRINGER VERLAG

: 1991

: European Journal of Biochemistry

: EUROPEAN JOURNAL OF BIOCHEMISTRY

: EUR J BIOCHEM

: 198

: 2

: 293

: 297

: 5

: 0014-2956

DOI: https://doi.org/10.1111/j.1432-1033.1991.tb16015.x

Interestingly, substitution of the tyrosines (Tyr51, Tyr55 and Tyr141) conserved with the amino acid sequence of yeast PP(i)ase [Lahti, R., Kolakowski, L. F., Heinonen, J., Vihinen, M., Pohjanoksa, K. and Cooperman, B. (1990) Biochim. Biophys. Acta 1038, 338-345] exerted the most drastic effects on the structure and activity of E. coli PP(i)ase. PP(i)ase variants YF51, YF55 and YF141 had 64%, 7% and 22% of the wild-type PP(i)ase activity, respectively. Furthermore, PP(i)ase variant YF141 had an increased sensitivity to heat denaturation, whereas mutant PP(i)ase YF55 displayed a profound conformational change, as demonstrated by the binding of the fluorescent dye 9-(diethylamino)-5H-benzo(alpha) phenoxazine-5-one (Nile red) that monitors the hydrophobicity of protein surfaces. None of the tyrosines of E. coli PP(i)ase seem to be essential for catalysis, but Tyr55 and Tyr141 are important for the structural integrity of E. coli PP(i)ase.