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1: Nat Struct Biol. 1995 Nov;2(11):1018-25.Links

A plasmid-encoded dihydrofolate reductase from trimethoprim-resistant bacteria has a novel D2-symmetric active site.

Narayana N, Matthews DA, Howell EE, Nguyen-huu X.

Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla 92093, USA.

Bacteria expressing R67-plasmid encoded dihydrofolate reductase (R67 DHFR) exhibit high-level resistance to the antibiotic trimethoprim. Native R67 DHFR is a 34,000 M(r) homotetramer which exists in equilibrium with an inactive dimeric form. The structure of native R67 DHFR has now been solved at 1.7 A resolution and is unrelated to that of chromosomal DHFR. Homotetrameric R67 DHFR has an unusual pore, 25 A in length, passing through the middle of the molecule. Two folate molecules bind asymmetrically within the pore indicating that the enzyme's active site consists of symmetry related binding surfaces from all four identical units.

PMID: 7583655 [PubMed - indexed for MEDLINE]

Structures reported by this article

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  • Folic Acid (Folvite® )

    Folic acid is used to treat or prevent folic acid deficiency. It is a B-complex vitamin needed by the body to manufacture red blood cells. A deficiency of this vitamin causes certain types of anemia (low red blood cell c...

  • Trimethoprim (Proloprim® )

    Trimethoprim eliminates bacteria that cause urinary tract infections. It is used in combination with other drugs to treat certain types of pneumonia. It also is used to treat 'travelers' diarrhea.' Antibiotics will not w...

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