Influence of divalent cations on the catalytic properties and secondary structure of unadenylylated glutamine synthetase from Azospirillum brasilense

被引：17

作者：

Antonyuk, LP

Smirnova, VE

Kamnev, AA

Serebrennikova, OB

Vanoni, MA

Zanetti, G

Kudelina, IA

Sokolov, OI

Ignatov, VV

机构：

[1] Russian Acad Sci, Inst Biochem & Physiol Plants & Microorganisms, Saratov 410015, Russia

[2] Univ Milan, Dipartimento Fisiol & Biochim Gen, I-20133 Milan, Italy

[3] Univ Insubria, Dipartimento Sci Chim Fis & Matemat, Como, Italy

[4] Russian Acad Sci, Shemyakin & Ovchinnikov Inst Bioorgan Chem, Moscow 117871, Russia

来源：

BIOMETALS | 2001年 / 14卷 / 01期

关键词：

glutamine synthetase; metals; Azospirillum brasilense; secondary structure;

D O I：

10.1023/A:1016640522299

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Fully unadenylylated glutamine synthetase (GS) from the endophytic bacterium Azospirillum brasilense Sp245 was isolated and purified. The enzyme was electrophoretically homogeneous and contained strongly bound metal ions, which could not be removed by dialysis. Mn2+, Mg2+, and Co2+ were found to be effective in supporting biosynthetic activity of the A. brasilense GS. Some kinetic properties of Mn2+-activated and Mg2+-activated unadenylylated GS were characterized. Circular dichroism analysis of the enzyme showed that the A. brasilense GS is a highly structured protein: 59% of its residues form alpha -helices and 13% beta -strands. Removal of the metal ions from the A. brasilense GS by treatment with EDTA resulted in alterations in the enzyme secondary structure.

引用

页码：13 / 22

页数：10

共 25 条

[1] IN-SITU LOCALIZATION OF AZOSPIRILLUM-BRASILENSE IN THE RHIZOSPHERE OF WHEAT WITH FLUORESCENTLY LABELED, RIBOSOMAL-RNA-TARGETED OLIGONUCLEOTIDE PROBES AND SCANNING CONFOCAL LASER MICROSCOPY [J].