1R48

Solution structure of the C-terminal cytoplasmic domain residues 468-497 of Escherichia coli protein ProP

Summary for 1R48

• Entry DOI: 10.2210/pdb1r48/pdb
• NMR Information: BMRB: 5972
• Descriptor: Proline/betaine transporter (1 entity in total)
• Functional Keywords: osmosensor, cytoplasmic, coiled-coil, antiparallel, two-stranded homodimer, transport protein
• Cellular location: Cell inner membrane; Multi-pass membrane protein: P30848
• Total number of polymer chains: 2
• Total formula weight: 7640.47

Authors

Zoetewey, D.L.,Tripet, B.P.,Kutateladze, T.G.,Overduin, M.J.,Wood, J.M.,Hodges, R.S. (deposition date: 2003-10-03, release date: 2003-12-23, Last modification date: 2024-05-22)

Primary citation

Zoetewey, D.L.,Tripet, B.P.,Kutateladze, T.G.,Overduin, M.J.,Wood, J.M.,Hodges, R.S.
Solution Structure of the C-terminal Antiparallel Coiled-coil Domain from Escherichia coli Osmosensor ProP.
J.Mol.Biol., 334:1063-1076, 2003

PubMed Abstract: Bacteria respond to increasing medium osmolality by accumulating organic solutes that are compatible with cellular functions. Transporter ProP of Escherichia coli, a proton symporter and a member of the major facilitator superfamily, senses osmotic shifts and responds by importing osmolytes such as glycine betaine. ProP contains a cytoplasmic, C-terminal extension that is essential for its activity. A peptide corresponding to the C-terminal extension of ProP forms a homodimeric alpha-helical coiled-coil even though some of its heptad a positions are not occupied by hydrophobic amino acid residues. Unexpectedly, amino acid replacement R488I, occurring at a heptad a position, destabilized the coiled-coil formed by the ProP peptide and attenuated the response of the intact transporter to osmotic upshifts in vivo. Thus, ProP was proposed to dimerize via an antiparallel coiled-coil. We used nuclear magnetic resonance (NMR) spectroscopy to determine the structure of the synthetic peptide corresponding to residues 468-497 of ProP. This region did form an antiparallel coil-coil in which critical residue R488 specifies the antiparallel coiled-coil orientation by forming stabilizing salt-bridges. Charged residues (both acidic and basic) are clustered on the c/g surface of the coiled-coil whereas polar residues are distributed on the b/e surface. This causes the structure to be bent, in contrast to other known antiparallel coiled-coils (those from the hepatitis delta antigen (PDB ID code 1A92) and the bovine F(1) ATPase inhibitor protein (PDB ID code 1HF9)). The coiled-coil and its possible importance for osmosensing are discussed.

PubMed: 14643666
DOI: 10.1016/j.jmb.2003.10.020

Experimental method

SOLUTION NMR