Microbiology Graduate Program
Leo W. Parks$Distinguished Lecture
Chasing the Nitrogenase Mechanism
Dr. Dennis R. Dean
Director, Life Sciences
University Distinguished Professor and Stroobants Professor of Biotechnology Virginia Tech
May 2, 2018
3503 Thomas Hall - Stephens Room 4:00 pm
Nitrogenase is a complex metalloenzyme that catalyzes the nucleotide dependent reduction of inert, metabolically intractable dinitrogen gas to a form, ammonia, that can be metabolized by living organisms. There are three types of nitrogenases produced in nature. One of these has Mo as a constituent of its active site cofactor and the other two, called “alternative nitrogenases”, have either V or Fe substituted for Mo in their active site cofactors. Of historical significance is that both of the alternative nitrogenases were first identified, purified, and genetically characterized by Dr. Paul Bishop from North Carolina State University. Our laboratory focuses on the Mo-dependent nitrogenase, which is the best studied nitrogen-fixing system as well as the most prevalent in nature. There are two major research themes in our laboratory. One is the elucidation of the catalytic mechanism of nitrogenase and the other involves characterization of the pathways for assembly of the metal- containing cofactors required to support catalysis. In this lecture I will summarize the basic catalytic features of nitrogenase and describe a biochemical-genetic approach that was successfully used to identify where and how nitrogenase substrates interact with the active site. References: Keeping the nitrogen-fixation dream alive. PNAS 114: 3009. Mechanism of nitrogen fixation by nitrogenase: the next stage. Chem Reviews 114:4041
Host: Eric Miller; To meet with Dr. Dean, please contact Dwayne Barnes (firstname.lastname@example.org)
The Leo W. Parks Distinguished Lectureship in Microbial Physiology honors Dr. Parks in perpetuity for his selfless attitude and many contributions to the NC State University community. The lecture is made possible by the generous donors who helped establish a permanent endowment in the North Carolina Agricultural Foundation, Inc., with matching support from the Department of Microbiology in the College of Agriculture and Life Sciences at North Carolina State University.
Microbiology Graduate Program
Leo W. Parks Distinguished Lecture
Biosynthesis of modified tetrapyrroles & the construction of novel variants
Professor Martin Warren
School of Biosciences
University of Kent, Canterbury, United Kingdom
Tuesday, October 18, 2016 3503 Thomas Hall - Stephens Room 4:00 p.m.
Outside of proteins and nucleic acids, modified tetrapyrroles have probably had the greatest effect on the evolution of life mainly because this group of compounds are so intrinsically involved in all the major respiratory processes found in living systems. The modified tetrapyrroles comprise a metallo-prosthetic group fraternity that includes heme, chlorophyll, vitamin B12, siroheme and coenzyme F430 as part of its membership, thereby representing the so-called pigments of life. Modified tetrapyrroles are made along a branched biosynthetic pathway and symbolise some of the most complex “small molecules” made in Nature. The seminar will review some of the recent findings that have led to the elucidation of the biochemical pathways for heme, F430 and B12, revealing a panoply of red, orange, green, blue and yellow coloured intermediates. Using vitamin B12 as an example, it will be shown how it is possible to use this pathway knowledge for the construction of novel variants and analogues, and how these can be used to probe biological form and function.
Co-Hosted by Dr. Eric Miller, Department of Plant and Microbial Biology and Dr. Jon Lindsey, Department of Chemistry
Refreshments will be served at 3:45 p.m.
The Microbiology Graduate Program occassionally hosts invited speakers who present current research in microbiology and related disciplines. The MGP also attempts to announce seminars hosted by other programs across campus that would appear to be of broad interest to MGP participants. Seminars are frequently held in the Stephens Room, 3503 Thomas Hall.