Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

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Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 47485.48 
• Atom Count: 3274 
• Residue Count: 426 
• Unique protein chains: 1

4RV9

Crystal structure of MtmC in complex with SAH

• DOI: 10.2210/pdb4RV9/pdb

• Classification: TRANSFERASE
• Organism(s): Streptomyces argillaceus
• Expression System: Escherichia coli


• Deposited: 2014-11-25 Released: 2015-02-04 
• Deposition Author(s): Hou, C., Chen, J.-M., Rohr, J., Tsodikov, O.V.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.2 Å
• R-Value Free: 0.241 
• R-Value Work: 0.203 

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

• PubMed: 25587924 
• DOI: 10.1021/bi501462g
• Primary Citation of Related Structures:  
  4RVH, 4RVG, 4RVF, 4RVD


• 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. 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.

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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: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
D-mycarose 3-C-methyltransferase	A	426	Streptomyces argillaceus	Mutation(s): 0  Gene Names: mtmC
Find proteins for Q194Q4 (Streptomyces argillaceus) Go to UniProtKB:  Q194Q4

Small Molecules

Ligands 4 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
ZN	A	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N
ACT	A	ACETATE ION C2 H3 O2 QTBSBXVTEAMEQO-UHFFFAOYSA-M
CL	A	CHLORIDE ION Cl VEXZGXHMUGYJMC-UHFFFAOYSA-M
SAH	A	S-ADENOSYL-L-HOMOCYSTEINE C14 H20 N6 O5 S ZJUKTBDSGOFHSH-WFMPWKQPSA-N

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
CSO	A	L-PEPTIDE LINKING	C3 H7 N O3 S		CYS

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.2 Å
• R-Value Free: 0.241 
• R-Value Work: 0.203 
• Space Group: I 4₁ 2 2

Unit Cell:

Length (Å)	Angle (°)
a = 134.245	α = 90.00
b = 134.245	β = 90.00
c = 130.010	γ = 90.00

Software Package:

Software Name	Purpose
REFMAC	refinement
HKL-2000	data reduction
HKL-2000	data scaling
MOLREP	phasing
HKL-2000	data collection

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2014-11-25 
• Released Date: 2015-02-04 
• Deposition Author(s): Hou, C., Chen, J.-M., Rohr, J., Tsodikov, O.V.

Revision History 

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