January 2010

Retrospective: Richard I. Gumport (1937–2009)

 

Gumport

Photograph: Copyright Richard B. Hallick, all rights reserved. Reprinted with permission.

The international biochemical community has lost a valued colleague with the death of Richard I. (Dick) Gumport in Chicago on Oct. 13. Gumport devoted his research career to the study of enzymes that act on nucleic acid substrates and to the characterization of biologically important protein-nucleic acid interactions. Moreover, he contributed generously to his profession through his service as a journal editor, as an educator and administrator and through his commitment to the promotion of international scientific cooperation.

Born in Pocatello, Idaho, on June 23, 1937, Dick Gumport worked his way through the University of Chicago with a variety of jobs and received a Bachelor of Science in general biology in 1960. His lifelong commitment to nucleic acids and the enzymes that catalyze their reactions can be traced to his doctoral studies on RNA polymerase, completed in 1968 at the University of Chicago with Samuel B. Weiss. The commitment was strengthened and broadened by Dick’s subsequent research as a National Institutes of Health postdoctoral fellow with I. Robert Lehman at Stanford University from 1968 to 1971. With Lehman, he identified a covalent intermediate in the DNA ligase reaction, namely an adenylyl moiety derived from the NAD+ (or ATP, depending on the source of the enzyme) substrate linked to an active site lysine residue as a phosphoramide. Dick often cited his experiences in the Stanford biochemistry department as inspiration for his ideal of an academic department as a close-knit community of collaborating scholars.

Dick joined the faculty of the biochemistry department at the University of Illinois at Urbana-Champaign in 1971 and spent his entire career there. He was the first full-time faculty member in the fledging Urbana campus of the University of Illinois College of Medicine, and he devoted much energy to the biochemical education of medical students and to administrative service to the medical school. At Illinois, Dick’s research initially centered on phage T4 RNA ligase. In collaboration with Olke C. Uhlenbeck, he demonstrated that RNA ligase could be used to join oligoribonucleotides, and he developed this method as a valuable tool for synthesis of RNA oligomers of defined sequence. Subsequently, Dick extended the use of RNA ligase to the joining of oligodeoxyribonucleotides, which was widely adopted in DNA synthetic chemistry. Recognizing the extraordinary value of DNA oligomers of known sequence as research tools, Dick became one of the pioneers in adapting newly developing methods of chemical synthesis of DNA oligomers, which could then be joined to form larger oligomers using RNA ligase. DNA oligomers prepared in Dick’s lab were used in pioneering studies with techniques that are now universally used: site-directed mutagenesis, primers for sequencing, templates for in vitro synthesis of RNA and mapping the specificity of protein-nucleic acid interactions. Often, Dick gave his oligomers to other researchers with no expectation of co-authorship.

Dick and Jeffrey Gardner, his colleague in Illinois’ microbiology department, conducted a productive collaboration for more than 20 years. They investigated the mechanism of site-specific recombination in bacteriophage lambda via characterization of integrase, integration host factor (IHF) and Xis and FIS interactions with DNA and the roles of these interactions in the regulation of the directionality of recombination and in forming nucleoprotein complexes. They also collaborated on research on the mechanism of transcription attenuation in regulation of the Escherichia coli threonine biosynthetic operon.

Dick’s interest in DNA synthesis led him to develop methods for the incorporation of base analogues into synthetic oligomers for use in detailed characterization of DNA recognition by proteins, both in collaboration with others and in his own laboratory. He conducted an extensive program of research into DNA recognition by the EcoRI and RsrI restriction endonucleases and methyltransferases, a group of four proteins chosen because they all bind to the same DNA sequence but catalyze different reactions and have little amino acid sequence homology. His studies provided valuable insight into the details of DNA recognition by these enzymes.

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