1st International and 10th National Iranian Conference on Bioinformatics

Identifying Thermostability Characteristics of Family A DNA Polymerases

Paper ID : 1099-ICB10

Authors:

Seddigheh Borhani *

Abstract:

DNA polymerases create complimentary DNA strand in living cells and are crucial to genome transmission and maintenance. All of these enzymes possess similar human right-handed fold which contain of thumb, fingers and palm subdomains and contribute to polymerization activities. These enzymes classified to 7 evolutionary families A, B, C, D, X, Y and RT based on amino acid sequences analysis and biochemical characteristics. Family A DNA polymerases exist on extended range of organisms included mesophilic, thermophilic and hyper thermophilic bacteria, participate in DNA replication and repair and have broad application in molecular biology and biotechnology. In this study, we attempt to detect factors play a role in thermostability properties of this family member despite their remarkable similarities in structure and function. For this purpose, similarities and differences in amino acid sequences, structure and dynamics of these enzymes have inspected. Our results demonstrated that thermophilic and hyper thermophilic enzymes have more charged, aromatic and polar residues than mesophilic ones, and consequently show further electrostatic and cation-pi interactions. In addition, in thermophilic enzymes, Tryptophan, Histidine and aliphatic residues tend to position in buried states more than mesophilic enzymes. These residues within their aliphatic parts increase hydrophobic core packing and therefore enhance thermostability of these enzymes. Moreover, molecular dynamic simulation results reveal that increasing of temperature impact mesophilic enzymes further than thermophilic ones, showing as rise in structural fluctuations and flexibilities.

Keywords:

Family A DNA Polymerases; Thermostability; Thermophilic Enzymes; Molecular Dynamic Simulations.

Status : Paper Accepted (Poster Presentation)