Maltose
Binding Protein:
Maltose Binding Protein (MBP) is a part
of the maltose/maltodextrin system of Eschericia coli bacteria,
which is responsible for the uptake and efficient catabolism of maltodextrins.
It is a complex regulatory and transport system involving many proteins
and protein complexes. For a recent review see W. Boos & H. Shuman,
Microbiology and Molecular Biology Reviews, 62, 204-229 (1998).
The figures shown are taken from the work of others and the references
are given in each case. The reader is encouraged to consult the original
reference for more detailed descriptions of the figures.
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Figure
1:
Location of "dominant-negative" and "suppressor" mutation sites on the structure of closed, ligand-bound MBP; maltose is shown in a ball and stick represen-tation. Dominant negative and suppressor mutation sites refer to the regions of the molecule critical to its maltose transport function. Other regions in which mutations are known that affect transport are indicated by the shaded areas. The figure was taken from the work of B.H. Shilton, H.A. Shuman & S.L. Mowbray, Journal of Molecular Biology, 264, 364-376 (1996). |
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Figure
2:
Crystal structures of the open (top) and closed (bottom) forms of MBP. The yellow structure represents maltose bound within the binding site. The figure is from the recent review of the maltose/maltodextrin system in E. coli by W. Boos & H. Shuman, Microbiology and Molecular Biology Reviews, 62, 204-229 (1998) (originally from B.H. Shilton, M.M. Flocco, M. Nilsson & S.L. Mowbray, Journal of Molecular Biology, 264, 350-363 (1996)). |
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Figure
3:
Perspective view of the superimposed backbone structure of unliganded (mauve) and maltose-bound (blue) MBP (looking into the binding cleft from the side) with bound maltose (ball-and-stick model). The direction and magnitude of the conformational change when going from the unliganded to the ligand-bound form are shown. The figure is from the recent review of the maltose/maltodextrin system in E. coli by W. Boos & H. Shuman, Microbiology and Molecular Biology Reviews, 62, 204-229 (1998) (originally from A.J. Sharff, L.E. Rodseth, J.C. Spurlino & F.A. Quiocho, Biochemistry, 31, 10657-10663 (1992)). |
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Figure
4:
Structure of MBP bound to maltose (right) and b-cyclodextrin (left), looking into the binding cleft from above. Ligands are shown in white, and residues Asp 41 and Ser 211 are highlighted in red against the rest of the MBP backbone. The distance between the C-a atoms of Asp 41 and Ser 211 in the maltose-MBP and b-cyclodextrin-MBP complexes is 15 and 24 A, respectively. The distance between the hydroxyl group of Ser 211 and the carboxyl carbon of Asp 41 in the maltose-MBP and b-cyclodextrin complexes is 11 and 23 A, respectively. The MBP-maltose structure shown is that of an MBP mutant, MalE178, which contains an insertion/deletion segment far removed from the binding pocket. The figure was taken from the work of J.A. Hall, T.E. Thorgeirsson, J. Lu, Y.-K. Shin & H. Nikaido, Journal of Biological Chemistry, 272, 17610-17614 (1997) (originally from A.J. Sharff, L.E. Rodseth, S. Szmelcman, M. Hofnung & F.A. Quiocho, Journal of Molecular Biology, 246, 8-13 (1995)). |
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