Structure and function of the DNA repair enzyme exonuclease III from E. coli

Conference · Sat Dec 31 00:00:00 EST 1994

OSTI ID:134852

Kuo, C F ^[1]; Mol, C D; Thayer, M M ^[2]

---

1. Abbott Labs., Abbott Park, IL (United States)
2. Scripps Research Institute, La Jolla, CA (United States); and others

The three-dimensional structure of exonuclease III, the major AP DNA repair endonuclease of Escherichia coli, has been determined using X-ray crystallographic methods. The atomic model was fit to an electron density map calculated with phases obtained from three ismorphous heavy atom derivatives. The overall chain fold of exonuclease III is that of a compact {alpha},{beta}-protein. The pair of extended {beta}-pleated sheets pack against each other in an approximately parallel fashion to form the hydrophobic core of a four-layered sandwich structure. These {beta} sheets are flanked by four {alpha}-helices that form the outer two layers of the fold. The individual strands of the {beta}-sheets are in a mostly antiparallel configuration and are linked by extensive loop regions that connect adjoining strands. The structure contains internal symmetry with the two extended {beta}-sheets and four {alpha}-helices related by a pseudo-twofold axis running approximately down the center of the two sheets. This internal symmetry is not mirrored in the structure of the loop regions, nor is it detectable within the amino acid sequence. There is a {open_quotes}groove{close_quotes} between the {beta}-sheets at one end of the molecule that is bordered by several of the exposed loop regions and may be significant for DNA binding.

• Research Organization: New York Academy of Sciences, New York, NY (United States)
• OSTI ID: 134852
• Report Number(s): CONF-9307221-; CNN: Grant GM 46312; Grant 2 T32 AG00080-14; TRN: 95:007741-0018
• Resource Relation: Conference: DNA damage: effects on DNA structure and protein recognition, Burlington, VT (United States), 31 Jul - 4 Aug 1993; Other Information: PBD: 1994; Related Information: Is Part Of DNA damage: Effects on DNA structure and protein recognition; Wallace, S.S.; Van Houten, B.; Kow, Yoke Wah [eds.]; PB: 395 p.
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
DNA
DNA REPAIR
STRUCTURE-ACTIVITY RELATIONSHIPS
MUTATIONS
GENETIC EFFECTS
GENETIC RADIATION EFFECTS
OXIDATION
ENDONUCLEASES
GENES
CRYSTAL STRUCTURE
HYDROXYL RADICALS
ANIMAL CELLS
GROWTH
HYDROGEN PEROXIDE
ESCHERICHIA COLI
IONIZING RADIATIONS
ENZYMES
CRYSTALLOGRAPHY
AMINO ACIDS
PROTEINS