Biological Assembly 1  

 3D View: Structure | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 21.75 kDa 
• Atom Count: 1415 
• Modelled Residue Count: 162 
• Deposited Residue Count: 207 
• Unique protein chains: 1

1EH7

METHYLATED HUMAN O6-ALKYLGUANINE-DNA ALKYLTRANSFERASE

• DOI: 10.2210/pdb1EH7/pdb

• Classification: TRANSFERASE
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2000-02-18 Released: 2000-04-12 
• Deposition Author(s): Daniels, D.S., Tainer, J.A.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Free: 0.229 
• R-Value Work: 0.199 

Literature

Active and alkylated human AGT structures: a novel zinc site, inhibitor and extrahelical base binding.

Daniels, D.S., Mol, C.D., Arvai, A.S., Kanugula, S., Pegg, A.E., Tainer, J.A.

(2000) EMBO J 19: 1719-1730

• PubMed: 10747039 
• DOI: 10.1093/emboj/19.7.1719
• Primary Citation of Related Structures:  
  1EH6, 1EH7, 1EH8


• PubMed Abstract: 
  

Human O(6)-alkylguanine-DNA alkyltransferase (AGT), which directly reverses endogenous alkylation at the O(6)-position of guanine, confers resistance to alkylation chemotherapies and is therefore an active anticancer drug target. Crystal structures of active human AGT and its biologically and therapeutically relevant methylated and benzylated product complexes reveal an unexpected zinc-stabilized helical bridge joining a two-domain alpha/beta structure. An asparagine hinge couples the active site motif to a helix-turn-helix (HTH) motif implicated in DNA binding. The reactive cysteine environment, its position within a groove adjacent to the alkyl-binding cavity and mutational analyses characterize DNA-damage recognition and inhibitor specificity, support a structure-based dealkylation mechanism and suggest a molecular basis for destabilization of the alkylated protein. These results support damaged nucleotide flipping facilitated by an arginine finger within the HTH motif to stabilize the extrahelical O(6)-alkylguanine without the protein conformational change originally proposed from the empty Ada structure. Cysteine alkylation sterically shifts the HTH recognition helix to evidently mechanistically couple release of repaired DNA to an opening of the protein fold to promote the biological turnover of the alkylated protein.

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Organizational Affiliation: 

The Skaggs Institute for Chemical Biology, Department of Molecular Biology, MB-4, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037-1027, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
O6-ALKYLGUANINE-DNA ALKYLTRANSFERASE	A	207	Homo sapiens	Mutation(s): 0  Gene Names: MGMT EC: 2.1.1.63
UniProt & NIH Common Fund Data Resources
Find proteins for P16455 (Homo sapiens) Explore P16455  Go to UniProtKB:  P16455
PHAROS:  P16455 GTEx:  ENSG00000170430

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
ZN	B [auth A]	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
SMC	A	L-PEPTIDE LINKING	C4 H9 N O2 S		CYS

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Free: 0.229 
• R-Value Work: 0.199 
• Space Group: P 3₁ 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 71.401	α = 90
b = 71.401	β = 90
c = 76.325	γ = 120

Software Package:

Software Name	Purpose
CNS	refinement
DENZO	data reduction
SCALEPACK	data scaling
CNS	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2000-02-18 
• Released Date: 2000-04-12 
Deposition Author(s): Daniels, D.S., Tainer, J.A.

Revision History  

• Version 1.0: 2000-04-12
  Type: Initial release
  
• Version 1.1: 2007-10-16
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance