Assignment of the hyperfine-shifted H-1-NMR signals of the heme in the oxygen sensor FixL from Rhizobium meliloti

被引:22
作者
Bertolucci, C
Ming, LJ
Gonzalez, G
GillesGonzalez, MA
机构
[1] UNIV S FLORIDA, INST BIOMOL SCI, TAMPA, FL 33620 USA
[2] OHIO STATE UNIV, DEPT MICROBIOL, COLUMBUS, OH 43210 USA
[3] OHIO STATE UNIV, CTR PLANT BIOTECHNOL, COLUMBUS, OH 43210 USA
来源
CHEMISTRY & BIOLOGY | 1996年 / 3卷 / 07期
关键词
FixL; myoglobin; nitrogen fixation; NMR; sensor kinase;
D O I
10.1016/S1074-5521(96)90147-7
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
Background: The Rhizobial oxygen sensor FixL is a hemoprotein with kinase activity. On binding of strong-field ligands, a change of the ferrous or ferric hems iron from high to low spin reversibly inactivates the kinase. This spin-state change and other information on the heme pocket have been inferred from enzymatic assays, absorption spectra and mutagenesis studies. We set out to investigate the spin-state of the FixL heme and to identify the hyperfine-shifted heme-proton signals by NMR spectroscopy. Results: Using one-dimensional NMR we directly observed the high- and low-spin nature of the met- and cyanomet-fixL. heme domain, respectively. We determined the hyperfine-shifted H-1-NMR signals of the heme and the proximal histidine by one- and two-dimensional spectroscopy and note the absence of distal histidine signals. Conclusions: These findings support the spin-state mechanism of FixL regulation. They establish that the site of heme coordination is a histidine residue and strongly suggest that a distal histidine is absent. With a majority of the heme resonances identified, one- and two-dimensional NMR techniques can be extended to provide structural and mechanistic information about the residues that line the heme pocket.
引用
收藏
页码:561 / 566
页数:6
相关论文
共 29 条
[1]   OXYGEN REGULATION OF NIFA TRANSCRIPTION INVITRO [J].
AGRON, PG ;
DITTA, GS ;
HELINSKI, DR .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1993, 90 (08) :3506-3510
[2]   COMPLETE HEME PROTON HYPERFINE RESONANCE ASSIGNMENTS OF THE GLYCERA-DIBRANCHIATA COMPONENT-IV METCYANO MONOMER HEMOGLOBIN [J].
ALAM, SL ;
SATTERLEE, JD .
BIOCHEMISTRY, 1994, 33 (13) :4008-4018
[3]   UNAMBIGUOUS HEME PROTON HYPERFINE RESONANCE ASSIGNMENTS OF A MONOMERIC HEMOGLOBIN FROM GLYCERA-DIBRANCHIATA FACILITATED WITH A COMPLETELY DEUTERATED PROTEIN [J].
ALAM, SL ;
SATTERLEE, JD .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1995, 117 (01) :49-53
[4]  
[Anonymous], 1989, NUCL OVERHAUSER EFFE, DOI DOI 10.1002/MRC.1260280819
[5]  
BERLINER LJ, 1992, NMR PARAMAGNETIC MOL
[6]   NUCLEAR-MAGNETIC-RESONANCE OF PARAMAGNETIC METALLOPROTEINS [J].
BERTINI, I ;
TURANO, P ;
VILA, AJ .
CHEMICAL REVIEWS, 1993, 93 (08) :2833-2932
[7]   2-DIMENSIONAL H-1-NMR STUDIES OF THE PARAMAGNETIC METALLOENZYME COPPER-NICKEL SUPEROXIDE-DISMUTASE [J].
BERTINI, I ;
LUCHINAT, C ;
MING, LJ ;
PICCIOLI, M ;
SOLA, M ;
VALENTINE, JS .
INORGANIC CHEMISTRY, 1992, 31 (22) :4433-4435
[8]  
Bertini I., 1986, NMR of Paramagnetic Molecules in Biological Systems
[9]   PROTON NUCLEAR MAGNETIC-RESONANCE STUDY OF THE RELAXATION BEHAVIOR AND KINETIC LABILITY OF EXCHANGEABLE PROTONS IN THE HEME POCKET OF CYANOMETMYOGLOBIN [J].
CUTNELL, JD ;
LAMAR, GN ;
KONG, SB .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1981, 103 (12) :3567-3572
[10]  
Ernst RR, 1987, PRINCIPLES NUCL MAGN