Crystallization and preliminary X-ray analysis of SNR 141-An N-terminal fragment of staphylococcal nuclease R

摘要

STAPHYLOCOCCAL nuclease (SNase A, EC 3.1.4.7), which hydrolyzes the phosphodiester bond of DNA and RNA, and releases 3'-phosphate mononucleotides and dinucleotides, consists of 149 amino acid residues (MW = 16 807) without sulfhydryl and disulfide groups. SNase A was originally derived from Staphylococcus aureus. Later the gene of the enzyme was cloned and inserted into several expression systems. Its crystal structure was detected at high resolution , showing that it has a single tryptophan residue(W140) buried in a hy-drophobic environment. SNase A is extensively used as an important model in the research of enzymatic mechanism, thermodynamic stability and kinetics of protein folding.