Dept. of Genetics, Cell Biology, and Development
6-160 Jackson Hall
321 Church St.
Minneapolis, MN 55455
Office: 4-114 BSBE, (612) 624-3053
Lab: 4-206 BSBE, (612) 624-2754
Fax: (612) 626-6140
email: robert-b@biosci.cbs.umn.edu
An essential characteristic of living cells is their ability to transport specific solutes across a semi-permeable membrane. An important pathway for the uptake of many different types of hydrophilic solutes is via membrane bound proteins which function as cation/solute cotransporters or symporters. This type of transporter is able to cotransport a solute with a cation so that the energy within a cation electrochemical gradient can be harnessed to drive the secondary active transport of the solute.
Our research lab is interested in the transport of ions and small molecules across cellular membranes. We study two different categories of transporters: sugar transporters and metal transporters. Both categories are symporters that couple the uptake of the solute with the uptake of hydrogen ions.
With regard to sugar transport, our lab has focused on the lactose permease found in E. coli. Our current studies involve an analysis of permease structure and function using genetic approaches and biophysical approaches. The metal transporters that we study are involved in the uptake of iron (Fe+2) and manganese (Mn+2) into cells. They are part of the NRAMP family that is found in bacteria, plants, and animals. With regard to mammals, NRAMP transporters are found in intestinal cells and are needed for the uptake of iron into the body. Human genetic diseases are known which affect the regulation of iron transporters. Our study of iron transporters is directed in several areas. These include regulation, structure/function, and their potential role in human disease.
Hrodey, H.A. and R.J. Brooker (2003) Role of Conserved Acidic Residues in MntH,
the
NRAMP homologue of Escherichia coli. (Manuscript in preparation).
Johnson, J.L., and R.J. Brooker (2003) Role of Glu-126 and Arg-144 in the Lactose Permease of Escherichia coli. Biochemistry, in press. Patzlaff JS. Zhang J. Brooker RJ. Barry BA. (2002) An isotope-edited FT-IR study of a symporter, the lactose permease. Biochemistry 41, 7366-72.
Green, A.L., and R.J. Brooker (2001) A face on transmembrane segment 8 of the lactose permease is important for transport activity. Biochemistry 40, 12220-9.
Johnson, J.L., Lockheart M.S. and R.J. Brooker (2001) A Triple Mutant, K319N/H322Q/E325. of the Lactose Permease Cotransports H+ with Thiodigagalactoside. J. Memb. Biol. 181, 215-224.
Pazdernik,N.J., Matzke, E.A., Jessen-Marshall, A.E., and R.J. Brooker (2000) Roles of Charged Residues in the Conserved Motif, G-X-X-X-D/E-R/K-X-G-[X]-R/K-R/K,of the Lactose Permease of,Escherichia coli. J. Memb. Biol. 174, 31-40.
Green, A.L., Anderson, E., and R.J. Brooker (2000) A Revised Model for the Structure and Function of the Lactose Permease. Evidence that a Face on Transmembrane Segment 2 Is Important for Conformational Changes. J. Biol. Chem. 275, 23, 240-23,246.
Patzlaff, J.S., Brooker, R.J., and B.A. Barry (2000) A Reaction-induced Fourier Transform-Infrared Spectroscopic Study of the Lactose Permease. J. Biol. Chem. 275,28,695-28,000.
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