3jyr

<StructureSection load='3jyr' size='340' side='right' caption='[[3jyr]], [[Resolution|resolution]] 1.75&Aring;' scene=''>

<table><tr><td colspan='2'>[[3jyr]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_typhimurium"_loeffler_1892 "bacillus typhimurium" loeffler 1892]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3JYR OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3JYR FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACR:ALPHA-ACARBOSE'>ACR</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">malE, STM4229 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=90371 "Bacillus typhimurium" Loeffler 1892])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3jyr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3jyr OCA], [http://pdbe.org/3jyr PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3jyr RCSB], [http://www.ebi.ac.uk/pdbsum/3jyr PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3jyr ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/MALE_SALTY MALE_SALTY]] Involved in the high-affinity maltose membrane transport system. Initial receptor for the active transport of and chemotaxis toward maltooligosaccharides.

<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/jy/3jyr_consurf.spt"</scriptWhenChecked>

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== Publication Abstract from PubMed ==

GacH is the solute binding protein (receptor) of the putative oligosaccharide ATP-binding cassette transporter GacFG, encoded in the acarbose biosynthetic gene cluster (gac) from Streptomyces glaucescens GLA.O. In the context of the proposed function of acarbose (acarviosyl-1,4-maltose) as a 'carbophor,' the transporter, in complex with a yet to be identified ATPase subunit, is supposed to mediate the uptake of longer acarbose homologs and acarbose for recycling purposes. Binding assays using isothermal titration calorimetry identified GacH as a maltose/maltodextrin-binding protein with a low affinity for acarbose but with considerable binding activity for its homolog, component 5C (acarviosyl-1,4-maltose-1,4-glucose-1,1-glucose). In contrast, the maltose-binding protein of Salmonella typhimurium (MalE) displays high-affinity acarbose binding. We determined the crystal structures of GacH in complex with acarbose, component 5C, and maltotetraose, as well as in unliganded form. As found for other solute receptors, the polypeptide chain of GacH is folded into two distinct domains (lobes) connected by a hinge, with the interface between the lobes forming the substrate-binding pocket. GacH does not specifically bind the acarviosyl group, but displays specificity for binding of the maltose moiety in the inner part of its binding pocket. The crystal structure of acarbose-loaded MalE showed that two glucose units of acarbose are bound at the same region and position as maltose. A comparative analysis revealed that in GacH, acarbose is buried deeper into the binding pocket than in MalE by exactly one glucose ring shift, resulting in a total of 18 hydrogen-bond interactions versus 21 hydrogen-bond interactions for MalE(acarbose). Since the substrate specificity of ATP-binding cassette import systems is determined by the cognate binding protein, our results provide the first biochemical and structural evidence for the proposed role of GacHFG in acarbose metabolism.

 

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== References ==

[[Category: Bacillus typhimurium loeffler 1892]]

[[Category: Bulut, H]]

[[Category: Licht, A]]

[[Category: Schneider, E]]

[[Category: Vahedi-Faridi, A]]

[[Category: Transport protein]]