1r48: Difference between revisions
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{{STRUCTURE_1r48| PDB=1r48 | SCENE= }} | |||
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'''Solution structure of the C-terminal cytoplasmic domain residues 468-497 of Escherichia coli protein ProP''' | '''Solution structure of the C-terminal cytoplasmic domain residues 468-497 of Escherichia coli protein ProP''' | ||
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==About this Structure== | ==About this Structure== | ||
1R48 is a [[Single protein]] structure | 1R48 is a [[Single protein]] structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1R48 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Wood, J M.]] | [[Category: Wood, J M.]] | ||
[[Category: Zoetewey, D L.]] | [[Category: Zoetewey, D L.]] | ||
[[Category: | [[Category: Antiparallel]] | ||
[[Category: | [[Category: Coiled-coil]] | ||
[[Category: | [[Category: Cytoplasmic]] | ||
[[Category: | [[Category: Osmosensor]] | ||
[[Category: | [[Category: Two-stranded homodimer]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 07:03:16 2008'' | |||
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Revision as of 04:03, 3 May 2008
Solution structure of the C-terminal cytoplasmic domain residues 468-497 of Escherichia coli protein ProP
Overview
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.
About this Structure
1R48 is a Single protein structure. Full crystallographic information is available from OCA.
Reference
Solution structure of the C-terminal antiparallel coiled-coil domain from Escherichia coli osmosensor ProP., Zoetewey DL, Tripet BP, Kutateladze TG, Overduin MJ, Wood JM, Hodges RS, J Mol Biol. 2003 Dec 12;334(5):1063-76. PMID:14643666 Page seeded by OCA on Sat May 3 07:03:16 2008
