His research focusses on the structure, mechanism, and regulation of bacterial transcription complexes, and on the development of inhibitors of bacterial transcription as antituberculosis agents and broad-spectrum antibacterial agents. His research employs tools of structural biology, biophysics, and drug-discovery.

He served for sixteen years as editor of the Journal of Molecular Biology. He has served on the National Institutes of Health Molecular Biology Study Section and on National Institutes of Health special emphasis panels. He is a member of the Institutional Biosafety Committee of Rutgers University, and he has been a member of the Antimicrobial Resistance Committee of the Infectious Diseases Society of America, the Working Group on Pathogen Security of the state of New Jersey, and the Controlling Dangerous Pathogens Project of the Center for International Security Studies. He has testified at US House and US Senate hearings on biosafety, biosecurity, and biorisk management.