粘质沙雷氏菌核酸酶的两种同工型。该酶的结晶及初步X射线研究。

Two isoforms of Serratia marcescens nuclease. Crystallization and preliminary X-ray investigation of the enzyme.

作者信息

Bannikova G E, Blagova E V, Dementiev A A, Mikchailov A M, Shlyapnikov S V, Varlamov V P, Vainshtein B K

机构信息

Bioengineriya, Centre, Institute of Molecular Biology, USSR Academy of Sciences, Moscow.

出版信息

Biochem Int. 1991 Jul;24(5):813-22.

PMID:1663739

Abstract

Two isoforms of an extracellular endonuclease, nucleases Sm1 and Sm2, were purified from culture fluid of Serratia marcescens strain BIO MI by ligand-exchange chromatography on phosphocellulose and DEAE-Toyopearl 650S. The pI-values for nucleases Sm1 and Sm2 were found to be 7.1 and 6.7, respectively. The amino acid analysis and N-terminal amino acid sequencing of the proteins showed a significant degree of homology between the enzymes. The nuclease Sm1 has been crystallized from ammonium sulfate solution by the vapour diffusion technique. The crystals belong to the space group P2(1)2(1)2(1) with unit cell constants a = 69.0, b = 106.7, c = 74.8 A, contain two molecules in an asymmetric unit, packing density Vm = 2.3 A/Da, and diffract to at least 1.5 A resolution. The Pt- and UO2-derivatives of the protein were obtained. Preliminary X-ray investigation of nuclease Sm2 crystals was carried out.

摘要

通过在磷酸纤维素和DEAE - Toyopearl 650S上进行配体交换色谱法，从粘质沙雷氏菌菌株BIO MI的培养液中纯化出一种细胞外核酸酶的两种同工型，即核酸酶Sm1和Sm2。发现核酸酶Sm1和Sm2的pI值分别为7.1和6.7。蛋白质的氨基酸分析和N端氨基酸测序表明这两种酶之间具有显著的同源性。核酸酶Sm1已通过气相扩散技术从硫酸铵溶液中结晶出来。晶体属于空间群P2(1)2(1)2(1)，晶胞参数a = 69.0、b = 106.7、c = 74.8 Å，一个不对称单位中含有两个分子，堆积密度Vm = 2.3 Å/Da，并且衍射分辨率至少为1.5 Å。获得了该蛋白质的铂和二氧化铀衍生物。对核酸酶Sm2晶体进行了初步的X射线研究。