PMID- 25941396
OWN - NLM
STAT- MEDLINE
DCOM- 20160428
LR  - 20211203
IS  - 1091-6490 (Electronic)
IS  - 0027-8424 (Print)
IS  - 0027-8424 (Linking)
VI  - 112
IP  - 20
DP  - 2015 May 19
TI  - Mechanism of pyranopterin ring formation in molybdenum cofactor biosynthesis.
PG  - 6347-52
LID - 10.1073/pnas.1500697112 [doi]
AB  - The molybdenum cofactor (Moco) is essential for all kingdoms of life, plays 
      central roles in various biological processes, and must be biosynthesized de 
      novo. During Moco biosynthesis, the characteristic pyranopterin ring is 
      constructed by a complex rearrangement of guanosine 5'-triphosphate (GTP) into 
      cyclic pyranopterin (cPMP) through the action of two enzymes, MoaA and MoaC 
      (molybdenum cofactor biosynthesis protein A and C, respectively). Conventionally, 
      MoaA was considered to catalyze the majority of this transformation, with MoaC 
      playing little or no role in the pyranopterin formation. Recently, this view was 
      challenged by the isolation of 3',8-cyclo-7,8-dihydro-guanosine 5'-triphosphate 
      (3',8-cH2GTP) as the product of in vitro MoaA reactions. To elucidate the 
      mechanism of formation of Moco pyranopterin backbone, we performed biochemical 
      characterization of 3',8-cH2GTP and functional and X-ray crystallographic 
      characterizations of MoaC. These studies revealed that 3',8-cH2GTP is the only 
      product of MoaA that can be converted to cPMP by MoaC. Our structural studies 
      captured the specific binding of 3',8-cH2GTP in the active site of MoaC. These 
      observations provided strong evidence that the physiological function of MoaA is 
      the conversion of GTP to 3',8-cH2GTP (GTP 3',8-cyclase), and that of MoaC is to 
      catalyze the rearrangement of 3',8-cH2GTP into cPMP (cPMP synthase). Furthermore, 
      our structure-guided studies suggest that MoaC catalysis involves the dynamic 
      motions of enzyme active-site loops as a way to control the timing of interaction 
      between the reaction intermediates and catalytically essential amino acid 
      residues. Thus, these results reveal the previously unidentified mechanism behind 
      Moco biosynthesis and provide mechanistic and structural insights into how 
      enzymes catalyze complex rearrangement reactions.
FAU - Hover, Bradley M
AU  - Hover BM
AD  - Department of Biochemistry, Duke University Medical Center, Durham, NC 27710.
FAU - Tonthat, Nam K
AU  - Tonthat NK
AD  - Department of Biochemistry, Duke University Medical Center, Durham, NC 27710.
FAU - Schumacher, Maria A
AU  - Schumacher MA
AD  - Department of Biochemistry, Duke University Medical Center, Durham, NC 27710 
      ken.yoko@duke.edu maria.schumacher@duke.edu.
FAU - Yokoyama, Kenichi
AU  - Yokoyama K
AD  - Department of Biochemistry, Duke University Medical Center, Durham, NC 27710 
      ken.yoko@duke.edu maria.schumacher@duke.edu.
LA  - eng
SI  - PDB/4PYA
SI  - PDB/4PYD
GR  - R01 GM074815/GM/NIGMS NIH HHS/United States
GR  - R01 GM112838/GM/NIGMS NIH HHS/United States
GR  - GM074815/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20150504
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
RN  - 0 (Carbon Isotopes)
RN  - 0 (Coenzymes)
RN  - 0 (Escherichia coli Proteins)
RN  - 0 (Metalloproteins)
RN  - 0 (MoaC protein, E coli)
RN  - 0 (Molybdenum Cofactors)
RN  - 0 (Pteridines)
RN  - 0 (Pterins)
RN  - 0 (pyranopterin)
RN  - ATN6EG42UQ (molybdenum cofactor)
RN  - EC 3.- (Hydrolases)
RN  - EC 3.3.1.2 (S-adenosylmethionine enzyme MoaA, Staphylococcus aureus)
SB  - IM
MH  - Carbon Isotopes
MH  - Coenzymes/*biosynthesis
MH  - Escherichia coli Proteins/chemistry/genetics/isolation & purification/*metabolism
MH  - Hydrolases/chemistry/isolation & purification/*metabolism
MH  - Magnetic Resonance Spectroscopy
MH  - Metalloproteins/*biosynthesis
MH  - *Models, Molecular
MH  - Molecular Structure
MH  - Molybdenum Cofactors
MH  - Mutagenesis, Site-Directed
MH  - Protein Conformation
MH  - Pteridines
MH  - Pterins/*chemistry
PMC - PMC4443348
OTO - NOTNLM
OT  - cPMP synthase
OT  - enzymatic rearrangement
OT  - molybdenum cofactor
OT  - pterin biosynthesis
OT  - radical SAM enzyme
COIS- The authors declare no conflict of interest.
EDAT- 2015/05/06 06:00
MHDA- 2016/04/29 06:00
PMCR- 2015/11/19
CRDT- 2015/05/06 06:00
PHST- 2015/05/06 06:00 [entrez]
PHST- 2015/05/06 06:00 [pubmed]
PHST- 2016/04/29 06:00 [medline]
PHST- 2015/11/19 00:00 [pmc-release]
AID - 1500697112 [pii]
AID - 201500697 [pii]
AID - 10.1073/pnas.1500697112 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 2015 May 19;112(20):6347-52. doi: 
      10.1073/pnas.1500697112. Epub 2015 May 4.