Stephen Charles Kowalczykowski ("Steve K") is a Distinguished Professor o
Microbiology and Molecular Genetics
at th
University of California at Davis
His research focuses on the biochemistry and molecular biology of

DNA repair DNA repair is a collection of processes by which a cell (biology), cell identifies and corrects damage to the DNA molecules that encode its genome. A weakened capacity for DNA repair is a risk factor for the development of cancer. DNA is cons ...

and

homologous recombination Homologous recombination is a type of genetic recombination in which genetic information is exchanged between two similar or identical molecules of double-stranded or single-stranded nucleic acids (usually DNA as in Cell (biology), cellular organi ...

. His lab combines fluorescence microscopy, optical trapping and

microfluidics Microfluidics refers to a system that manipulates a small amount of fluids (10−9 to 10−18 liters) using small channels with sizes of ten to hundreds of micrometres. It is a multidisciplinary field that involves molecular analysis, molecular bi ...

to manipulate and visualize single molecules of

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

and the

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

s involved in processing and repairing

. He calls this scientific approach, "visual biochemistry". Stephen Kowalczykowski was elected to the American Society for Arts and Science in 2005, th
National Academy of Sciences
in 2007 and was a Harvey Society Lecturer at Rockefeller University in 2012.

Education and career

Stephen Kowalczykowski studied chemistry (B.S.) at

Rensselaer Polytechnic Institute Rensselaer Polytechnic Institute (; RPI) is a private university, private research university in Troy, New York, United States. It is the oldest technological university in the English-speaking world and the Western Hemisphere. It was establishe ...

in 1972 and earned his Ph.D. in Chemistry/Biochemistry at

Georgetown University Georgetown University is a private university, private Jesuit research university in Washington, D.C., United States. Founded by Bishop John Carroll (archbishop of Baltimore), John Carroll in 1789, it is the oldest Catholic higher education, Ca ...

in 1976. His dissertation title was "Physical-Chemistry studies of Sickle Cell Hemoglobin." He then worked as a postdoctoral researcher wit
Dr. Peter von Hippel
at the

University of Oregon The University of Oregon (UO, U of O or Oregon) is a Public university, public research university in Eugene, Oregon, United States. Founded in 1876, the university is organized into nine colleges and schools and offers 420 undergraduate and gra ...

Health Sciences Institute, where he began studying the physical chemistry of protein-nucleic interactions. He began his academic research career at Northwestern University Medical School in 1981 and later moved to the University of California at Davis in 1991. He is one of the world's foremost experts on

RecA RecA is a 38 kilodalton protein essential for the repair and maintenance of DNA in bacteria. Structural and functional homologs to RecA have been found in all kingdoms of life. RecA serves as an archetype for this class of homologous DNA repair p ...

, the defining member of a ubiquitous class of DNA strand-exchange proteins that are essential for homologous recombination, a pathway that maintains genomic integrity by repairing broken

. His lab has made significant contributions to the fields of

, homologous recombination and the biophysics of DNA helicases.

Scientific contributions

A few of his lab's notable scientific contributions include the structural and molecular mechanism of DNA end resection by RecBCD (''E. coli'') and DNA2-Sgs1-RPA and regulatory stimulation by Top3-Rmi1 and Mre11-Rad50-Xrs2 (''S. cerevisiae''), the kinetics of

filament nucleation and growth and regulation by RecFOR (''E. coli''), the purification and molecular mechanism of the human breast cancer susceptibility gene

BRCA2 ''BRCA2'' and BRCA2 () are human genes and their protein products, respectively. The official symbol (BRCA2, italic for the gene, nonitalic for the protein) and the official name (originally breast cancer 2; currently BRCA2, DNA repair associate ...

(humans), the mechanism of the

Holliday junction A Holliday junction is a branched nucleic acid structure that contains four double-stranded arms joined. These arms may adopt one of several conformations depending on buffer salt concentrations and the sequence of nucleobases closest to the j ...

dissolution by the Bloom's Syndrome helicase (BLM) homologue, Sgs1 (''S. cerevisiae''), and the mechanism of the 3-dimensional homology search catalyzed by

(''E. coli'').

Publications

Research publications on Pubmed

References

{{DEFAULTSORT:Kowalczykowski, Stephen American microbiologists American molecular biologists 21st-century American biologists University of California, Davis faculty Georgetown University alumni Rensselaer Polytechnic Institute alumni Members of the United States National Academy of Sciences Fellows of the American Academy of Arts and Sciences Living people Year of birth missing (living people)