Full electronic structure calculation of the biological activity in P173L enzyme

Abstract

ABSTRACT:The biological activity variation along with the temperature in the heatsensitive mutant P173L with 26316 electrons has been studied by full electronic structure calculation and parallel molecular dynamics from temperature 302-318 K. The change of the energy gap between the frontier orbital energy level occupied by each of the four residues and the lowest unoccupied molecular orbital energy level was worked out as an index to quantify the biological activity variation. We reproduced the experimental results suggested by Fomenkov et al.: Residues GLU77, ASP94, GLU111, and GLU113 were essential to the enzyme catalytic function and the enzyme cleavage activity is decreased in turn at temperatures 303, 310, and 315 K. Moreover, our calculations revealed more elaborate information that was not found by the experiment: There is a range of temperature (ϳ307-313 K) between the experimental temperatures 303-315 K in which the enzyme cleavage activity increases.