 |
PDBsum entry 4xxh
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Gene regulation
|
PDB id
|
|
|
|
4xxh
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Crystal structure of the effector-Binding domain of the trehalose-Repressor of escherichia coli, A member of the laci family, In its complexes with inducer trehalose-6-Phosphate and noninducer trehalose.
|
|
|
Authors
|
|
U.Hars,
R.Horlacher,
W.Boos,
W.Welte,
K.Diederichs.
|
|
|
Ref.
|
|
Protein Sci, 1998,
7,
2511-2521.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
The crystal structure of the Escherichia coli trehalose repressor (TreR) in a
complex with its inducer trehalose-6-phosphate was determined by the method of
multiple isomorphous replacement (MIR) at 2.5 A resolution, followed by the
structure determination of TreR in a complex with its noninducer trehalose at
3.1 A resolution. The model consists of residues 61 to 315 comprising the
effector binding domain, which forms a dimer as in other members of the LacI
family. This domain is composed of two similar subdomains each consisting of a
central beta-sheet sandwiched between alpha-helices. The effector binding pocket
is at the interface of these subdomains. In spite of different physiological
functions, the crystal structures of the two complexes of TreR turned out to be
virtually identical to each other with the conformation being similar to those
of the effector binding domains of the LacI and PurR in complex with their
effector molecules. According to the crystal structure, the noninducer trehalose
binds to a similar site as the trehalose portion of trehalose-6-phosphate. The
binding affinity for the former is lower than for the latter. The noninducer
trehalose thus binds competitively to the repressor. Unlike the phosphorylated
inducer molecule, it is incapable of blocking the binding of the repressor
headpiece to its operator DNA. The ratio of the concentrations of
trehalose-6-phosphate and trehalose thus is used to switch between the two
alternative metabolic uses of trehalose as an osmoprotectant and as a carbon
source.
|
|
|
|
|
|
|
|
Figure 1.
Fig. 1. Structure of theTreR effector bindindmaindimerwithboundinducermoleculeTre6P in ribbonrepresentation.Th/-strands
are colore blue ndnamedAthrough K. The a-helices are inyellowandnamedsequentiallyas I through X. Thegraphicwasmade
with MOLSCRIPT(Kraulis,1991).TheN-terminalsubdoainiscomposed of strandA(64-69),heix I (75-91). trand B (94-99),
helix II (104-115), strand C(121-124),heli III 132-138). strandD(142-144),strandE(153-157).helix X (284-299).andstrand K
(307-310). The C-terminalsubdomain consists of helix IV (159-172),strand F (178-181),helix (192-204).strandG(210-212),
helix VI (218-224),helix VII (226-228), strand H (235-238),helix VIII (241-253), strand 260-264).helix M (268-273),and
strand J (278-281).Theconnectingcross-over are at residues 157-158,282-283,and310-311.
|
|
Figure 3.
Fig. 3. Scheme of hydrogenbonds of Tre6PinitscomplexwithTreR.Thedistancesbetweenacceptors an donorsaregiven A.
|
|
|
|
|
|
The above figures are
reprinted
from an Open Access publication published by the Protein Society:
Protein Sci
(1998,
7,
2511-2521)
copyright 1998.
|
|
|
Secondary reference #1
|
|
|
Title
|
|
Achieving high quality ligand chemistry in protein-Li crystal structures for drug design
|
|
|
Authors
|
|
O.S.Smart,
G.Bricogne.
|
|
|
Ref.
|
|
multifaceted roles of ...
|
|
|
|
|
|
|
|
