4RV9

Crystal structure of MtmC in complex with SAH

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.205 

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Literature

Structural Insight into MtmC, a Bifunctional Ketoreductase-Methyltransferase Involved in the Assembly of the Mithramycin Trisaccharide Chain.

Chen, J.M., Hou, C., Wang, G., Tsodikov, O.V., Rohr, J.

(2015) Biochemistry 54: 2481-2489

  • DOI: 10.1021/bi501462g
  • Primary Citation of Related Structures:  
    4RVH, 4RVD, 4RVF, 4RVG, 4RV9

  • PubMed Abstract: 

    • More and more post-PKS tailoring enzymes are recognized as being multifunctional and codependent on other tailoring enzymes. One of the recently discovered intriguing examples is MtmC, a bifunctional TDP-4-keto-d-olivose ketoreductase-methyltransferase, which-in codependence with glycosyltransferase MtmGIV-is a key contributor to the biosynthesis of the critical trisaccharide chain of the antitumor antibiotic mithramycin (MTM), produced by Streptomyces argillaceus ...

    More and more post-PKS tailoring enzymes are recognized as being multifunctional and codependent on other tailoring enzymes. One of the recently discovered intriguing examples is MtmC, a bifunctional TDP-4-keto-d-olivose ketoreductase-methyltransferase, which-in codependence with glycosyltransferase MtmGIV-is a key contributor to the biosynthesis of the critical trisaccharide chain of the antitumor antibiotic mithramycin (MTM), produced by Streptomyces argillaceus. We report crystal structures of three binary complexes of MtmC with its methylation cosubstrate SAM, its coproduct SAH, and a nucleotide TDP as well as crystal structures of two ternary complexes, MtmC-SAH-TDP-4-keto-d-olivose and MtmC-SAM-TDP, in the range of 2.2-2.7 Å resolution. The structures reveal general and sugar-specific recognition and catalytic structural features of MtmC. Depending on the catalytic function that is conducted by MtmC, it must bind either NADPH or SAM in the same cofactor binding pocket. A tyrosine residue (Tyr79) appears as a lid covering the sugar moiety of the substrate during the methyl transfer reaction. This residue swings out of the active site by ~180° in the absence of the substrate. This unique conformational change likely serves to release the methylated product and, possibly, to open the active site for binding the bulkier cosubstrate NADPH prior to the reduction reaction.

    Organizational Affiliation: 

    Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536-0596, United States.



Macromolecules
Find similar proteins by: 
(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
D-mycarose 3-C-methyltransferaseA426Streptomyces argillaceusMutation(s): 0 
Gene Names: mtmC
UniProt
Find proteins for Q194Q4 (Streptomyces argillaceus)
Explore Q194Q4 
Go to UniProtKB:  Q194Q4
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SAH (Subject of Investigation/LOI)
Query on SAH
Download Ideal Coordinates CCD File 
 C [auth A]S-ADENOSYL-L-HOMOCYSTEINE
C14 H20 N6 O5 S
ZJUKTBDSGOFHSH-WFMPWKQPSA-N		 Ligand Interaction
ZN
Query on ZN
Download Ideal Coordinates CCD File 
 B [auth A]ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N		 Ligand Interaction
ACT
Query on ACT
Download Ideal Coordinates CCD File 
 D [auth A]ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M		 Ligand Interaction
CL
Query on CL
Download Ideal Coordinates CCD File 
 E [auth A]CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M		 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
CSO
Query on CSO		AL-PEPTIDE LINKINGC3 H7 N O3 SCYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.205 
  • Space Group: I 41 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 134.245α = 90
b = 134.245β = 90
c = 130.01γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
MOLREPphasing
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-02-04
    Type: Initial release
  • Version 1.1: 2015-03-18
    Changes: Database references
  • Version 1.2: 2015-05-13
    Changes: Database references