Bradyrhizobium japonicum porphobilinogen synthase uses two Mg(II) and monovalent cations

被引:41
作者
Petrovich, RM [1 ]
Litwin, S [1 ]
Jaffe, EK [1 ]
机构
[1] FOX CHASE CANC CTR,INST CANC RES,PHILADELPHIA,PA 19111
关键词
D O I
10.1074/jbc.271.15.8692
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
Bradyrhizobium japonicum porphobilinogen synthase (B. japonicum PBGS) has been purified and characterized from an overexpression system in an Escherichia coli host (Chauhan, S., and O'Brian, M. R. (1995) J. Biol. Chem. 270, 19823-19827). B. japonicum PBGS defines a new class of PBGS protein, type IV (classified by metal ion content), which utilizes a catalytic Mg-A present at a stoichiometry of 4/octamer, an allosteric Mg-C present at a stoichiometry of 8/octamer, and a monovalent metal ion, K+. However, the divalent Mg-B or Zn-B present in some other PBGS is not present in B. japonicum PBGS. Under optimal conditions, the K-d for Mg-A is < 0.2 mu M, and the K-d for Mg-C is about 40 mu M. The response of B. japonicum PBGS activity to monovalent and divalent cations is mutually dependent and varies dramatically with pH. B. japonicum PBGS is also found to undergo a dynamic equilibrium between active multimeric species and inactive monomers under assay conditions, a kinetic characteristic not reported for other PBGSs. B. japonicum PBGS is the first PBGS that has been rigorously demonstrated to lack a catalytic Zn-A. However, consistent with prior predictions, B. japonicum PBGS can bind Zn(II) (presumably as Zn-A) at a stoichiometry of 4/octamer with a K-d of 200 mu M; but this high concentration is outside a physiologically significant range.
引用
收藏
页码:8692 / 8699
页数:8
相关论文
共 35 条
[1]  
BEVAN DR, 1980, J BIOL CHEM, V255, P2030
[2]  
BOESE QF, 1991, J BIOL CHEM, V266, P17060
[3]   Crystallization and preliminary X-ray diffraction studies of 5-chlorolevulinate-modified bovine porphobilinogen synthase and the Pb-II-complexed enzyme [J].
Carrell, HL ;
Glusker, JP ;
Shimoni, L ;
Keefe, LJ ;
Afshar, C ;
Volin, M ;
Jaffe, EK .
ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY, 1996, 52 :419-421
[4]   BRADYRHIZOBIUM-JAPONICUM DELTA-AMINOLEVULINIC-ACID DEHYDRATASE IS ESSENTIAL FOR SYMBIOSIS WITH SOYBEAN AND CONTAINS A NOVEL METAL-BINDING DOMAIN [J].
CHAUHAN, S ;
OBRIAN, MR .
JOURNAL OF BACTERIOLOGY, 1993, 175 (22) :7222-7227
[5]   A MUTANT BRADYRHIZOBIUM-JAPONICUM DELTA-AMINOLEVULINIC-ACID DEHYDRATASE WITH AN ALTERED METAL REQUIREMENT FUNCTIONS IN-SITU FOR TETRAPYRROLE SYNTHESIS IN SOYBEAN ROOT-NODULES [J].
CHAUHAN, S ;
OBRIAN, MR .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1995, 270 (34) :19823-19827
[6]   2 DIFFERENT ZINC SITES IN BOVINE 5-AMINOLEVULINATE DEHYDRATASE DISTINGUISHED BY EXTENDED X-RAY ABSORPTION FINE-STRUCTURE [J].
DENT, AJ ;
BEYERSMANN, D ;
BLOCK, C ;
HASNAIN, SS .
BIOCHEMISTRY, 1990, 29 (34) :7822-7828
[7]  
HAMMING RW, 1962, NUMERICAL METHODS SC, P81
[8]  
Jaffe E. K., 1993, COMMENTS INORG CHEM, V15, P67
[9]   CHARACTERIZATION OF THE ROLE OF THE STIMULATORY MAGNESIUM OF ESCHERICHIA-COLI PORPHOBILINOGEN SYNTHASE [J].
JAFFE, EK ;
ALI, S ;
MITCHELL, LW ;
TAYLOR, KM ;
VOLIN, M ;
MARKHAM, GD .
BIOCHEMISTRY, 1995, 34 (01) :244-251
[10]   N-15 AND C-13 NMR-STUDIES OF LIGANDS BOUND TO THE 280000-DALTON PROTEIN PORPHOBILINOGEN SYNTHASE ELUCIDATE THE STRUCTURES OF ENZYME-BOUND PRODUCT AND A SCHIFF-BASE INTERMEDIATE [J].
JAFFE, EK ;
MARKHAM, GD ;
RAJAGOPALAN, JS .
BIOCHEMISTRY, 1990, 29 (36) :8345-8350