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Hitesh Sharma Graduate Student Center for Structural Biology Phone:
(203) 432-5625 Email: hitesh.sharma {at} yale.edu |
Using crystallographic techniques to further understand E. coli RNA polymerase initiation of DNA transcription
Summary
RNA polymerase is one of the largest protein complexes in the cell and is responsible for transcribing DNA sequence into RNA. The core complex consists of b, b', w, and 2 a subunits. Although it can bind non-specific DNA, it has a considerably higher affinity for promoter sequences when combined with the appropriate s factor to form the holoenzyme. Upon binding, the s factor melts the DNA downstream of the promoter helping to form the transcription initiation bubble and converting the RNA polymerase to an open complex from the closed one. This presumably results in the template strand to enter the polymerase's active site. With the help of the catalytic Mg2+, the enzyme begins to synthesize an RNA transcript.
The goal of my project is to capture the holoenzyme bound to DNA promoter in the crystal form, so that initiation of transcription can be better understood.
Model of Thermus aquaticus RNA
polymerase with bound promoter DNA forming the initiation complex for
ribonucleotide incorporation.
(Ref.1 below)
Publication:
Commentary on this work:
1. Murakami, K.S., Darst, S.A., (2003) Current Opinion in Structural Biology. 13, 31-39.
2. Murakami, K.S., Masuda, S., Campbell, E.A., Muzzin, O., Darst, S.A. (2002) Science. 296, 1285-1290.
3. Lawson, C.L., Swigon, D., Murakami, K.S., Darst, S.A., Berman, H.M., Ebright, R.H. (2004) Current Opinion in Structural Biology. 14, 10-20.
4. Vassylyev, D.G., Sekine, S,, Laptenko, O., Lee, J., Vassylyeva, M.N., Borukhov, S., Yokoyama, S. (2002) Nature. 417, 712-719.