 |
|
Title
|
|
Structure determination of OppA at 2.3 A resolution using multiple-wavelength anomalous dispersion methods.
|
|
|
Authors
|
|
I.D.Glover,
R.C.Denny,
N.D.Nguti,
S.M.McSweeney,
S.H.Kinder,
A.W.Thompson,
E.J.Dodson,
A.J.Wilkinson,
J.R.Tame.
|
|
|
Ref.
|
|
Acta Crystallogr D Biol Crystallogr, 1995,
51,
39-47.
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
OppA is a 58.8 kDa bacterial transport protein involved in the transport of
peptides across the cytoplasmic membrane of Gram-negative bacteria. It binds
peptides from two to five residues in length but with little sequence
specificity. OppA from Salmonella typhimurium has been cloned and expressed in
E. coli and the protein cocrystallized with uranyl acetate, producing two
distinct crystal forms with different uranium sites. Multiple-wavelength data
collected about the uranium L(III) edge have been collected at the Daresbury
Synchrotron Radiation Source (SRS) to a nominal resolution limit of 2.3 A.
Maximum-likelihood phasing methods have been used in phase determination from
the multiple-wavelength data giving a readily interpretable electron-density
map, without any density modification. The electron-density map, calculated at
2.3 A resolution shows OppA to be a bilobal, principally beta-stranded,
three-domain protein. The tri-lysine ligand molecule can be clearly seen in the
peptide-binding site between the two lobes.
|
|
|
|