Hitesh Sharma
From WikidChem
Hitesh is a graduate student in Tom Steitz's Lab .
Research
I am involved in researching the structural aspects of E. coli transcription by X-ray crystallography. The central dogma of biology states that proteins cannot be carriers of genetic information and therefore every organism is programmed to carry out the processes of DNA replication, transcription, and translation. Since resources are limited, each one of these stages is tightly regulated.
To achieve maximum transcription output, an activator binds to the RNA polymerase causing DNA and/or protein conformational changes which ultimately lead to a decrease of the energy barrier for the rate limiting conversion of the closed complex to the open one. Regulation in this case is achieved by CAP, a transcription factor that bends DNA in the presence of cAMP. To study the allosteric mechanism of subunit anti-cooperativity, I am currently trying to solve the structure of CAP without cAMP.
I am also in the process stabilizing the RNA polymerase itself for crystallization. Inherently, it exists in a variety of different conformations. To make matters more complicated, it is a multi-subunit enzyme and many of its subunits also have a variety of flexibility. A handful of bacterial RNAP structures have been solved, however, the processes of initiation, inhibition, and termination are still unresolved crystallographically. The strategy that I am using involves combining and transposing different elements of each process.
