1mpn: Difference between revisions

Revision as of 14:57, 21 February 2008

MALTOPORIN MALTOTRIOSE COMPLEX

OverviewOverview

BACKGROUND: Maltoporin (which is encoded by the lamB gene) facilitates the translocation of maltodextrins across the outer membrane of E. coli. In particular, it is indispensable for the transport of long maltooligosaccharides, as these do not pass through non-specific porins. An understanding of this intriguing capability requires elucidation of the structural basis. RESULTS: The crystal structures of maltoporin in complex with maltose, maltotriose and maltohexaose reveal an extended binding site within the maltoporin channel. The maltooligosaccharides are in apolar van der Waals contact with the 'greasy slide', a hydrophobic path that is composed of aromatic residues and located at the channel lining. At the constriction of the channel the sugars are tightly surrounded by protein side chains and form an extensive hydrogen-bonding network with ionizable amino-acid residues. CONCLUSION: Hydrophobic interactions with the greasy slide guide the sugar into and through the channel constriction. The glucosyl-binding subsites at the channel constriction confer stereospecificity to the channel along with the ability to scavenge substrate at low concentrations.

About this StructureAbout this Structure

1MPN is a Single protein structure of sequence from Escherichia coli with as ligand. Full crystallographic information is available from OCA.

ReferenceReference

Crystal structures of various maltooligosaccharides bound to maltoporin reveal a specific sugar translocation pathway., Dutzler R, Wang YF, Rizkallah P, Rosenbusch JP, Schirmer T, Structure. 1996 Feb 15;4(2):127-34. PMID:8805519

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OCA

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-[[Image:1mpn.jpg|left|200px]]<br /><applet load="1mpn" size="450" color="white" frame="true" align="right" spinBox="true"
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 caption="1mpn, resolution 3.2&Aring;" />
 '''MALTOPORIN MALTOTRIOSE COMPLEX'''<br />
 ==Overview==
-BACKGROUND: Maltoporin (which is encoded by the lamB gene) facilitates the, translocation of maltodextrins across the outer membrane of E. coli. In, particular, it is indispensable for the transport of long, maltooligosaccharides, as these do not pass through non-specific porins., An understanding of this intriguing capability requires elucidation of the, structural basis. RESULTS: The crystal structures of maltoporin in complex, with maltose, maltotriose and maltohexaose reveal an extended binding site, within the maltoporin channel. The maltooligosaccharides are in apolar van, der Waals contact with the 'greasy slide', a hydrophobic path that is, composed of aromatic residues and located at the channel lining. At the, constriction of the channel the sugars are tightly surrounded by protein, side chains and form an extensive hydrogen-bonding network with ionizable, amino-acid residues. CONCLUSION: Hydrophobic interactions with the greasy, slide guide the sugar into and through the channel constriction. The, glucosyl-binding subsites at the channel constriction confer, stereospecificity to the channel along with the ability to scavenge, substrate at low concentrations.
+BACKGROUND: Maltoporin (which is encoded by the lamB gene) facilitates the translocation of maltodextrins across the outer membrane of E. coli. In particular, it is indispensable for the transport of long maltooligosaccharides, as these do not pass through non-specific porins. An understanding of this intriguing capability requires elucidation of the structural basis. RESULTS: The crystal structures of maltoporin in complex with maltose, maltotriose and maltohexaose reveal an extended binding site within the maltoporin channel. The maltooligosaccharides are in apolar van der Waals contact with the 'greasy slide', a hydrophobic path that is composed of aromatic residues and located at the channel lining. At the constriction of the channel the sugars are tightly surrounded by protein side chains and form an extensive hydrogen-bonding network with ionizable amino-acid residues. CONCLUSION: Hydrophobic interactions with the greasy slide guide the sugar into and through the channel constriction. The glucosyl-binding subsites at the channel constriction confer stereospecificity to the channel along with the ability to scavenge substrate at low concentrations.
 ==About this Structure==
-MPN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with MG as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1MPN OCA].
+MPN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=MG:'>MG</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MPN OCA].
 ==Reference==
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 [[Category: sugar transport]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 21:36:57 2007''
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