PMID- 16704267
OWN - NLM
STAT- MEDLINE
DCOM- 20070822
LR  - 20240312
IS  - 0002-7863 (Print)
IS  - 1520-5126 (Electronic)
IS  - 0002-7863 (Linking)
VI  - 128
IP  - 20
DP  - 2006 May 24
TI  - 1H NMR study of the magnetic properties and electronic structure of the hydroxide 
      complex of substrate-bound heme oxygenase from Neisseria meningitidis: influence 
      of the axial water deprotonation on the distal H-bond network.
PG  - 6657-68
AB  - The substrate and active site residues of the low-spin hydroxide complex of the 
      protohemin complex of Neisseria meningitidis heme oxygenase (NmHO) have been 
      assigned by saturation transfer between the hydroxide and previously 
      characterized aquo complex. The available dipolar shifts allowed the quantitation 
      of both the orientation and anisotropy of the paramagnetic susceptibility tensor. 
      The resulting positive sign, and reduced magnitude of the axial anisotropy 
      relative to the cyanide complex, dictate that the orbital ground state is the 
      conventional "d(pi)" (d(2)(xy)(d(xz), d(yz))(3)); and not the unusual "d(xy)" 
      (d(2)(xz)d(2)(yz)d(xy)) orbital ground state reported for the hydroxide complex 
      of the homologous heme oxygenase (HO) from Pseudomonas aeruginosa (Caignan, G.; 
      Deshmukh, R.; Zeng, Y.; Wilks, A.; Bunce, R. A.; Rivera, M. J. Am. Chem. Soc. 
      2003, 125, 11842-11852) and proposed as a signature of the HO distal cavity. The 
      conservation of slow labile proton exchange with solvent from pH 7.0 to 10.8 
      confirms the extraordinary dynamic stability of NmHO complexes. Comparison of the 
      diamagnetic contribution to the labile proton chemical shifts in the aquo and 
      hydroxide complexes reveals strongly conserved bond strengths in the distal 
      H-bond network, with the exception of the distal His53 N(epsilon)(1)H. The 
      iron-ligated water is linked to His53 primarily by a pair of nonligated, ordered 
      water molecules that transmit the conversion of the ligated H-bond donor (H(2)O) 
      to a H-bond acceptor (OH(-)), thereby increasing the H-bond donor strength of the 
      His53 side chain.
FAU - Ma, Li-Hua
AU  - Ma LH
AD  - Department of Chemistry, University of California, Davis, California 95616, USA.
FAU - Liu, Yangzhong
AU  - Liu Y
FAU - Zhang, Xuhang
AU  - Zhang X
FAU - Yoshida, Tadashi
AU  - Yoshida T
FAU - La Mar, Gerd N
AU  - La Mar GN
LA  - eng
GR  - R01 GM062830/GM/NIGMS NIH HHS/United States
GR  - R01 GM062830-07/GM/NIGMS NIH HHS/United States
GR  - GM 62830/GM/NIGMS NIH HHS/United States
GR  - HL 16087/HL/NHLBI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Am Chem Soc
JT  - Journal of the American Chemical Society
JID - 7503056
RN  - 0 (Hydroxides)
RN  - 059QF0KO0R (Water)
RN  - 42VZT0U6YR (Heme)
RN  - 9159UV381P (hydroxide ion)
RN  - EC 1.14.14.18 (Heme Oxygenase (Decyclizing))
SB  - IM
MH  - Anisotropy
MH  - Heme/chemistry
MH  - Heme Oxygenase (Decyclizing)/*chemistry
MH  - Hydrogen Bonding
MH  - Hydrogen-Ion Concentration
MH  - Hydroxides/*chemistry
MH  - Neisseria meningitidis/*enzymology
MH  - Nuclear Magnetic Resonance, Biomolecular
MH  - Thermodynamics
MH  - Water/chemistry
PMC - PMC2566968
MID - NIHMS63288
EDAT- 2006/05/18 09:00
MHDA- 2007/08/23 09:00
PMCR- 2008/10/13
CRDT- 2006/05/18 09:00
PHST- 2006/05/18 09:00 [pubmed]
PHST- 2007/08/23 09:00 [medline]
PHST- 2006/05/18 09:00 [entrez]
PHST- 2008/10/13 00:00 [pmc-release]
AID - 10.1021/ja0584626 [doi]
PST - ppublish
SO  - J Am Chem Soc. 2006 May 24;128(20):6657-68. doi: 10.1021/ja0584626.