INVOLVEMENT OF GROEL IN NIF GENE-REGULATION AND NITROGENASE ASSEMBLY

被引:59
作者
GOVEZENSKY, D [1 ]
GREENER, T [1 ]
SEGAL, G [1 ]
ZAMIR, A [1 ]
机构
[1] WEIZMANN INST SCI,DEPT BIOCHEM,IL-76100 REHOVOT,ISRAEL
关键词
D O I
10.1128/jb.173.20.6339-6346.1991
中图分类号
Q93 [微生物学];
学科分类号
071005 ; 100705 ;
摘要
Several approaches were used to study the role of GroEL, the prototype chaperonin, in the nitrogen fixation (nif) system. An Escherichia coli groEL mutant transformed with the Klebsiella pneumoniae nif gene cluster accumulated very low to nondetectable levels of nitrogenase components compared with the isogenic wild-type strain or the mutant cotransformed with the wild-type groE operon. In K. pneumoniae, overexpression of the E. coli groE operon markedly accelerated the rate of appearance of the MoFe protein and its constituent polypeptides after the start of derepression. The groEL mutation in E. coli decreased NifA-dependent beta-galactosidase expression from the nifH promoter but did not affect the constitutive expression of nifA from the tet promoter or ntr-controlled expression from the nifLA promoter. The possibility that GroEL is required for the correct folding of NifA was supported by coimmunoprecipitation of NifA with anti-GroEL antibodies. Kinetic analyses of nitrogenase assembly in S-35 pulse-chased K. pneumoniae pointed to the existence of high-molecular-weight intermediates in MoFe protein assembly and demonstrated the transient binding of newly synthesized NifH and NifDK to GroEL. Overall, these results indicate that GroEL fulfills both regulatory and structural functions in the nif system.
引用
收藏
页码:6339 / 6346
页数:8
相关论文
共 41 条
[21]   THE INTEGRATION HOST FACTOR STIMULATES INTERACTION OF RNA-POLYMERASE WITH NIFA, THE TRANSCRIPTIONAL ACTIVATOR FOR NITROGEN-FIXATION OPERONS [J].
HOOVER, TR ;
SANTERO, E ;
PORTER, S ;
KUSTU, S .
CELL, 1990, 63 (01) :11-22
[22]  
HOWARD KS, 1986, J BIOL CHEM, V261, P772
[23]   SEQUENCE OF THE LACZ GENE OF ESCHERICHIA-COLI [J].
KALNINS, A ;
OTTO, K ;
RUTHER, U ;
MULLERHILL, B .
EMBO JOURNAL, 1983, 2 (04) :593-597
[24]   ESCHERICHIA-COLI SECB PROTEIN ASSOCIATES WITH EXPORTED PROTEIN PRECURSORS INVIVO [J].
KUMAMOTO, CA .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1989, 86 (14) :5320-5324
[25]   EFFECTS OF MUTATIONS IN HEAT-SHOCK GENES GROES AND GROEL ON PROTEIN EXPORT IN ESCHERICHIA-COLI [J].
KUSUKAWA, N ;
YURA, T ;
UEGUCHI, C ;
AKIYAMA, Y ;
ITO, K .
EMBO JOURNAL, 1989, 8 (11) :3517-3521
[26]   CLEAVAGE OF STRUCTURAL PROTEINS DURING ASSEMBLY OF HEAD OF BACTERIOPHAGE-T4 [J].
LAEMMLI, UK .
NATURE, 1970, 227 (5259) :680-+
[27]  
Maniatis T., 1982, MOL CLONING
[28]  
Merrick M. J., 1988, Nitrogen fixation: Hundred years after. Proceedings of the 7th International Congress on Nitrogen Fixation, Koln (Cologne), FRG, March 13-20, 1988., P293
[29]  
Miller J.H., 1972, EXPT MOL GENETICS, P1