PMID- 28801051
OWN - NLM
STAT- MEDLINE
DCOM- 20171130
LR  - 20180917
IS  - 0005-2728 (Print)
IS  - 0005-2728 (Linking)
VI  - 1858
IP  - 11
DP  - 2017 Nov
TI  - The mechanism for oxygen reduction in cytochrome c dependent nitric oxide 
      reductase (cNOR) as obtained from a combination of theoretical and experimental 
      results.
PG  - 884-894
LID - S0005-2728(17)30118-4 [pii]
LID - 10.1016/j.bbabio.2017.08.005 [doi]
AB  - Bacterial NO-reductases (NOR) belong to the heme-copper oxidase (HCuO) 
      superfamily, in which most members are O(2)-reducing, proton-pumping enzymes. 
      This study is one in a series aiming to elucidate the reaction mechanisms of the 
      HCuOs, including the mechanisms for cellular energy conservation. One approach 
      towards this goal is to compare the mechanisms for the different types of HCuOs, 
      cytochrome c oxidase (CcO) and NOR, reducing the two substrates O(2) and NO. 
      Specifically in this study, we describe the mechanism for oxygen reduction in 
      cytochrome c dependent NOR (cNOR). Hybrid density functional calculations were 
      performed on large cluster models of the cNOR binuclear active site. Our results 
      are used, together with published experimental information, to construct a free 
      energy profile for the entire catalytic cycle. Although the overall reaction is 
      quite exergonic, we show that during the reduction of molecular oxygen in cNOR, 
      two of the reduction steps are endergonic with high barriers for proton uptake, 
      which is in contrast to oxygen reduction in CcO, where all reduction steps are 
      exergonic. This difference between the two enzymes is suggested to be important 
      for their differing capabilities for energy conservation. An additional result 
      from this study is that at least three of the four reduction steps are initiated 
      by proton transfer to the active site, which is in contrast to CcO, where 
      electrons always arrive before the protons to the active site. The roles of the 
      non-heme metal ion and the redox-active tyrosine in the active site are also 
      discussed.
CI  - Copyright (c) 2017 Elsevier B.V. All rights reserved.
FAU - Blomberg, Margareta R A
AU  - Blomberg MRA
AD  - Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 
      Stockholm SE-106 91, Sweden. Electronic address: margareta.blomberg@su.se.
FAU - Adelroth, Pia
AU  - Adelroth P
AD  - Department of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm 
      University, Stockholm SE-106 91, Sweden.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20170808
PL  - Netherlands
TA  - Biochim Biophys Acta Bioenerg
JT  - Biochimica et biophysica acta. Bioenergetics
JID - 101731706
RN  - 0 (Bacterial Proteins)
RN  - 31C4KY9ESH (Nitric Oxide)
RN  - 42VZT0U6YR (Heme)
RN  - 9007-43-6 (Cytochromes c)
RN  - EC 1.- (Oxidoreductases)
RN  - EC 1.7.2.5 (nitric-oxide reductase)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Bacterial Proteins/*chemistry/metabolism
MH  - Biocatalysis
MH  - Catalytic Domain
MH  - Cytochromes c/*chemistry/metabolism
MH  - Electron Transport Complex IV/*chemistry/metabolism
MH  - Heme/chemistry/metabolism
MH  - Kinetics
MH  - Molecular Dynamics Simulation
MH  - Nitric Oxide/chemistry/metabolism
MH  - Oxidation-Reduction
MH  - Oxidoreductases/*chemistry/metabolism
MH  - Oxygen/*chemistry/metabolism
MH  - Paracoccus denitrificans/*chemistry/enzymology
MH  - Protein Conformation
MH  - Quantum Theory
MH  - Thermodynamics
OTO - NOTNLM
OT  - Cellular energy conservation
OT  - Density functional theory
OT  - Electron transfer
OT  - Energy profile
OT  - Non-heme iron
OT  - Proton transfer
EDAT- 2017/08/13 06:00
MHDA- 2017/12/01 06:00
CRDT- 2017/08/13 06:00
PHST- 2017/04/11 00:00 [received]
PHST- 2017/06/29 00:00 [revised]
PHST- 2017/08/05 00:00 [accepted]
PHST- 2017/08/13 06:00 [pubmed]
PHST- 2017/12/01 06:00 [medline]
PHST- 2017/08/13 06:00 [entrez]
AID - S0005-2728(17)30118-4 [pii]
AID - 10.1016/j.bbabio.2017.08.005 [doi]
PST - ppublish
SO  - Biochim Biophys Acta Bioenerg. 2017 Nov;1858(11):884-894. doi: 
      10.1016/j.bbabio.2017.08.005. Epub 2017 Aug 8.