* Senior Investigator: Nancy G. Nossal

* Affiliation: Laboratory of Molecular and Cellular Biology, NIDDK

* Research: Structure and function of multi-enzyme DNA replication complexes.

* We have been studying the molecular mechanisms controlling DNA replication using a multi-enzyme system of proteins encoded by bacteriophage T4. We have developed procedures for the purification of the polymerase, polymerase accessory proteins, DNA binding protein, primase-helicase components, and RNaseH required for DNA - synthesis in this system. We are currently collaborating with Craig Hyde and Tim Mueser (Laboratory of Structural Biology, NIAMS), who are trying to crystallize these proteins.

* Personnel/Resources:

* Publications:

M.W. Frey, N.G. Nossal, T.L. Capson, & S.J. Benkovic (1993). Proc. Natl. Acad. Sci. USA 90:2579-2583. Construction and characterization of a bacteriophage T4 DNA polymerase deficient in 3'->5' exonuclease activity.

H.C. Hollingsworth, & N.G. Nossal (1991). J. Biol. Chem. 266:1888-1897. Bacteriophage T4 encodes an RNase H which removes primers made by the T4 DNA replication system in vitro.

T.C. Capson, S. Benkovic, & N.G. Nossal (1991). Cell 65:249-258. Protein-DNA cross-linking demonstrates stepwise ATP-dependent assembly of T4 DNA polymerase and its accessory proteins on the primer-template.

N.G. Nossal (1992). FASEB J. 6:871-878. Protein-protein interactions at a DNA replication fork: bacteriophage T4 as a model.

P. Spacciapoli, & N.G. Nossal (1993). J. Biol. Chem. (in press). A single mutation in bacteriophage T4 DNA polymerase (A737V, tsL141) decreases its processivity as a polymerase and increases its processivity as a 3'->5' exonuclease.

P. Spacciapoli, & N.G. Nossal (1993). J. Biol. Chem. (in press). Interaction of DNA polymerase and DNA helicase within the bacteriophage T4 DNA replication complex: leading strand synthesis by the T4 DNA polymerase mutant A737V (tsL141) requires the T4 gene 59 helicase assembly protein.

* Contact: Dr. N. Nossal, Bldg. 8, Room 2A-19. NIDDK, NIH, Bethesda, MD 20892.

Tel: (301) 496-2724 Fax: (301) 402-0240

Figure: Model of bacteriophage T4 DNA replication proteins at a replication fork.