In this biography
Quick facts
- Born
- 13 June 1946
- Birthplace
- Raton, NM, USA
- Country
- United States
- Nationality
- Not independently established
- Known for
- Reconstituting DNA mismatch repair and investigating how repair is directed to a particular strand
Why this life matters
Reconstituting DNA mismatch repair and investigating how repair is directed to a particular strand
Timeline
Key moments
Birth
Paul Modrich was born in Raton, NM, USA.
Defined repair system
Co-authored a reconstitution of methyl-directed mismatch correction.
Nobel recognition
Received Nobel recognition for the work described in the official award record.
From New Mexico to molecular biology
Paul Modrich was born in Raton, New Mexico, in 1946. At MIT, an introductory biology course helped direct his interests toward molecular research, and work with Ethan Signer introduced him to bacteriophage genetics. He moved to Stanford in 1968 for doctoral training with Robert Lehman, completing the degree in 1973. Postdoctoral work with Charles Richardson at Harvard Medical School continued his investigation of DNA-related enzymes. His research education connected genetic questions with biochemical methods for identifying what individual proteins actually did.
A Duke laboratory focused on mechanisms
Modrich moved to Duke University in 1976, where his early programme included EcoRI enzymes and the problem of locating specific recognition sites within a large DNA molecule. That interest in molecular recognition developed alongside the mismatch-repair work for which he became best known. The laboratory investigated a difficult distinction: detecting an incorrect base pair was not enough if repair then replaced the wrong strand. A useful mechanism needed to explain recognition, direction and the reactions that restored a correctly paired molecule.
Reconstructing a reaction from defined components
In 1989 Robert Lahue, Karin Au and Modrich reported DNA mismatch correction in a purified E. coli system. The reaction required multiple proteins rather than a single all-purpose repair enzyme. Its direction depended on methylation information at a GATC site separated from the mismatch. The work connected an observed correction with a defined set of biochemical participants. It also made different stages accessible to further experiments, allowing researchers to ask how a mismatch and a distant strand signal could be brought into one repair process.
A pathway rather than one isolated proofreading event
Modrich shared the 2015 Nobel Prize in Chemistry with Tomas Lindahl and Aziz Sancar for mechanistic studies of DNA repair. His programme also extended to human mismatch-repair systems, as his Nobel lectureโs comparison of bacterial and human mechanisms makes clear. The lasting contribution is a detailed biochemical approach to a process that protects genetic information. It showed how a final corrected molecule can be explained through coordinated recognition and processing steps, and why those steps must be investigated rather than inferred solely from the final outcome.
Quick answers
Frequently asked questions about Paul Modrich
- Why is strand choice important?
- Replacing one side of a mismatch can preserve the original information or install the error; repair must be directed appropriately.
- Did the 1989 study identify one enzyme doing every step?
- No. It reconstituted a strand-specific reaction with a defined set of proteins and chemical components.
Keep exploring
Lives connected to this story
- Roger Kornberg
Compare different biochemical programmes that reconstructed molecular mechanisms from defined components.
- Tomas Lindahl
Compare mismatch correction with removal of a chemically altered base.
Sources and further reading
Explore the evidence
These references support the biography and offer further reading. Official records, first-person accounts and independent reporting provide different perspectives; image records document attribution and licensing.
- 1. Lahue, Au and Modrich / Science, 1989DNA mismatch correction in a defined system
The 1989 reaction is identified as a defined E. coli biochemical system, rather than a universal methylation mechanism in all organisms.
- 2. Paul Modrich / Journal of Biological Chemistry, 1989Methyl-directed DNA mismatch correction
- 3. Nobel Prize OutreachPaul Modrich โ Nobel lecture
- 4. Nobel Prize OutreachPaul Modrich โ Facts
- 5. Nobel Prize OutreachPaul Modrich โ Biographical