Cummins Lab: Phosphorus, a mineral element found in rocks and bone, is a critical ingredient in fertilizers, pesticides, detergents and other industrial and household chemicals. Once phosphorus is mined from rocks, getting it into these products is hazardous and expensive, and chemists have been trying to streamline the process for decades.

Professor Christopher Cummins and one of his graduate students, Daniel Tofan, have developed a new way to attach phosphorus to organic compounds by first splitting the phosphorus with ultraviolet light. Their method, described in the Aug. 26 online edition of Angewandte Chemie, eliminates the need for chlorine, which is usually required for such reactions and poses health risks to workers handling the chemicals. Go to MIT News>>

Structural basis for activation of class Ib ribonucleotide reductase
Amie K. Boal, Joseph A. Cotruvo, Jr., JoAnne Stubbe, and Amy C. Rosenzweig
Science, published online August 5, 2010

The lab of Prof. Amy Rosenzweig (MIT Ph.D. 1994 from the Lippard group), in collaboration with the Stubbe lab, has crystallized a protein-protein complex essential for assembly of a dimanganese(III)-tyrosyl radical (Y•) cofactor in the class Ib ribonucleotide reductase (RNR) from E. coli. The class Ib RNRs are the primary aerobic route to the deoxynucleotide building blocks of DNA for many pathogenic bacteria.

Previous work by the Stubbe lab had demonstrated that formation of the dimanganese cofactor requires reaction of a flavodoxin-like protein, NrdI, with O2 to form the peroxide oxidant, H2O2 or HO2-, necessary for Y• formation. Crystallization of the complex between NrdI and the RNR subunit NrdF reveals a channel from the flavin cofactor in NrdI that reacts with O2 to the metal site in NrdF that allows for safe delivery of the reactive peroxide intermediate, supporting the proposed mechanism of cluster assembly.