1mpo
From Proteopedia
(New page: 200px<br /><applet load="1mpo" size="450" color="white" frame="true" align="right" spinBox="true" caption="1mpo, resolution 2.8Å" /> '''MALTOPORIN MALTOHEXAO...) |
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| - | [[Image:1mpo.jpg|left|200px]]<br /><applet load="1mpo" size=" | + | [[Image:1mpo.jpg|left|200px]]<br /><applet load="1mpo" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1mpo, resolution 2.8Å" /> | caption="1mpo, resolution 2.8Å" /> | ||
'''MALTOPORIN MALTOHEXAOSE COMPLEX'''<br /> | '''MALTOPORIN MALTOHEXAOSE COMPLEX'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: Maltoporin (which is encoded by the lamB gene) facilitates the | + | 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== | ==About this Structure== | ||
| - | 1MPO 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:// | + | 1MPO 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=1MPO OCA]. |
==Reference== | ==Reference== | ||
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[[Category: sugar transport]] | [[Category: sugar transport]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:57:45 2008'' |
Revision as of 11:57, 21 February 2008
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MALTOPORIN MALTOHEXAOSE COMPLEX
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.
About this Structure
1MPO is a Single protein structure of sequence from Escherichia coli with as ligand. Full crystallographic information is available from OCA.
Reference
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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