The Missing Electrostatic Interactions Between DNA Substrate and Sulfolobus solfataricus DNA Photolyase: What is the Role of Charged Amino Acids in Thermophilic DNA Binding Proteins?
DNA photolyase can be used to study how a protein with its required cofactor has adapted over a large temperature range. The enzymatic activity and thermodynamics of substrate binding for protein from Sulfolobus solfataricus were directly compared to protein from Escherichia coli. Turnover numbers and catalytic activity were virtually identical, but organic cosolvents may be necessary to maintain activity of the thermophilic protein at higher temperatures. UV-damaged DNA binding to the thermophilic protein is less favorable by ∼2 kJ/mol. The enthalpy of binding is ∼10 kJ/mol less exothermic for the thermophile, but the amount and type of surface area buried upon DNA binding appears to be somewhat similar. The most important finding was observed when ionic strength studies were used to separate binding interactions into electrostatic and nonelectrostatic contributions; DNA binding to the thermophilic protein appears to lack the electrostatic contributions observed with the mesophilic protein.
Department of Chemistry and Biochemistry, Montclair State University , 1 Normal Avenue, Montclair, New Jersey 07043, United States.
Yvonne M
YM
Gindt
Department of Chemistry and Biochemistry, Montclair State University , 1 Normal Avenue, Montclair, New Jersey 07043, United States.
Ban H
BH
Edani
Department of Chemistry and Biochemistry, Montclair State University , 1 Normal Avenue, Montclair, New Jersey 07043, United States.
Antonia
A
Olejnikova
Department of Chemistry and Biochemistry, Montclair State University , 1 Normal Avenue, Montclair, New Jersey 07043, United States.
Ariana N
AN
Roberts
Department of Chemistry, Temple University , 1801 N Broad Street, Philadelphia, Pennsylvania 19122, United States.
Sudipto
S
Munshi
Department of Chemistry, Temple University , 1801 N Broad Street, Philadelphia, Pennsylvania 19122, United States.
Robert J
RJ
Stanley
D000596:Amino Acids / Q000737:chemistry* / Q000378:metabolism; D002151:Calorimetry; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D055672:Static Electricity; D048229:Sulfolobus solfataricus / Q000201:enzymology*; D013696:Temperature
D000596:Amino Acids; D004268:DNA-Binding Proteins; D004247:DNA; D004255:Deoxyribodipyrimidine Photo-Lyase