 |
PDBsum entry 1eu8
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Sugar binding protein
|
PDB id
|
|
|
|
1eu8
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
Contents |
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
* Residue conservation analysis
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
The crystal structure of a liganded trehalose/maltose-Binding protein from the hyperthermophilic archaeon thermococcus litoralis at 1.85 a.
|
|
|
Authors
|
|
J.Diez,
K.Diederichs,
G.Greller,
R.Horlacher,
W.Boos,
W.Welte.
|
|
|
Ref.
|
|
J Mol Biol, 2001,
305,
905-915.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
We report the crystallization and structure determination at 1.85 A of the
extracellular, membrane-anchored trehalose/maltose-binding protein (TMBP) in
complex with its substrate trehalose. TMBP is the substrate recognition site of
the high-affinity trehalose/maltose ABC transporter of the hyperthermophilic
Archaeon Thermococcus litoralis. In vivo, this protein is anchored to the
membrane, presumably via an N-terminal cysteine lipid modification. The
crystallized protein was N-terminally truncated, resulting in a soluble protein
exhibiting the same binding characteristics as the wild-type protein. The
protein shows the characteristic features of a transport-related,
substrate-binding protein and is structurally related to the maltose-binding
protein (MBP) of Escherichia coli. It consists of two similar lobes, each formed
by a parallel beta-sheet flanked by alpha-helices on both sides. Both are
connected by a hinge region consisting of two antiparallel beta-strands and an
alpha-helix. As in MBP, the substrate is bound in the cleft between the lobes by
hydrogen bonds and hydrophobic interactions. However, compared to maltose
binding in MBP, direct hydrogen bonding between the substrate and the protein
prevails while apolar contacts are reduced. To elucidate factors contributing to
thermostability, we compared TMBP with its mesophilic counterpart MBP and found
differences known from similar investigations. Specifically, we find helices
that are longer than their structurally equivalent counterparts, and fewer
internal cavities.
|
|
|
|
|
|
|
|
Figure 1.
Figure 1. Ribbon model of TMBP with bound trehalose (shown
as a ball and stick model). The N-terminal and C-terminal lobes
are coloured yellow and blue, respectively. The bound trehalose
is shown as a bond model and coloured black; a-helices and
b-strands are labelled according to Figure 2(b).
|
|
Figure 3.
Figure 3. Stereo representation of a |3F[o] -2F[c]|
electron density map of TMBP at 2.4 s around the bound
a,a-trehalose moiety. Carbon atoms are coloured grey, nitrogen
atoms are coloured blue and oxygen atoms are coloured red. The
map is coloured green.
|
|
|
|
|
|
The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2001,
305,
905-915)
copyright 2001.
|
|
|
|
|
|
|
