1afb: Difference between revisions

New page: left|200px<br /><applet load="1afb" size="450" color="white" frame="true" align="right" spinBox="true" caption="1afb, resolution 1.9Å" /> '''STRUCTURAL BASIS OF G...
 
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'''STRUCTURAL BASIS OF GALACTOSE RECOGNITION IN C-TYPE ANIMAL LECTINS'''<br />


==Overview==
==STRUCTURAL BASIS OF GALACTOSE RECOGNITION IN C-TYPE ANIMAL LECTINS==
The asialoglycoprotein receptors and many other C-type (Ca2+-dependent), animal lectins specifically recognize galactose- or, N-acetylgalactosamine-terminated oligosaccharides. Analogous binding, specificity can be engineered into the homologous rat mannose-binding, protein A by changing three amino acids and inserting a glycine-rich loop, (Iobst, S. T., and Drickamer, K. (1994) J. Biol. Chem. 269, 15512-15519)., Crystal structures of this mutant complexed with beta-methyl galactoside, and N-acetylgalactosamine (GalNAc) reveal that as with wild-type, mannose-binding proteins, the 3- and 4-OH groups of the sugar directly, coordinate Ca2+ and form hydrogen bonds with amino acids that also serve, as Ca2+ ligands. The different stereochemistry of the 3- and 4-OH groups, in mannose and galactose, combined with a fixed Ca2+ coordination, geometry, leads to different pyranose ring locations in the two cases. The, glycine-rich loop provides selectivity against mannose by holding a, critical tryptophan in a position optimal for packing with the apolar face, of galactose but incompatible with mannose binding. The 2-acetamido, substituent of GalNAc is in the vicinity of amino acid positions, identified by site-directed mutagenesis (Iobst, S. T., and Drickamer, K., (1996) J. Biol. Chem. 271, 6686-6693) as being important for the formation, of a GalNAc-selective binding site.
<StructureSection load='1afb' size='340' side='right'caption='[[1afb]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1afb]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AFB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AFB FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.9&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=NGA:N-ACETYL-D-GALACTOSAMINE'>NGA</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1afb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1afb OCA], [https://pdbe.org/1afb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1afb RCSB], [https://www.ebi.ac.uk/pdbsum/1afb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1afb ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MBL1_RAT MBL1_RAT] Calcium-dependent lectin involved in innate immune defense. Binds mannose, fucose and N-acetylglucosamine on different microorganisms and activates the lectin complement pathway. Binds to late apoptotic cells, as well as to apoptotic blebs and to necrotic cells, but not to early apoptotic cells, facilitating their uptake by macrophages (By similarity).
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/af/1afb_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1afb ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The asialoglycoprotein receptors and many other C-type (Ca2+-dependent) animal lectins specifically recognize galactose- or N-acetylgalactosamine-terminated oligosaccharides. Analogous binding specificity can be engineered into the homologous rat mannose-binding protein A by changing three amino acids and inserting a glycine-rich loop (Iobst, S. T., and Drickamer, K. (1994) J. Biol. Chem. 269, 15512-15519). Crystal structures of this mutant complexed with beta-methyl galactoside and N-acetylgalactosamine (GalNAc) reveal that as with wild-type mannose-binding proteins, the 3- and 4-OH groups of the sugar directly coordinate Ca2+ and form hydrogen bonds with amino acids that also serve as Ca2+ ligands. The different stereochemistry of the 3- and 4-OH groups in mannose and galactose, combined with a fixed Ca2+ coordination geometry, leads to different pyranose ring locations in the two cases. The glycine-rich loop provides selectivity against mannose by holding a critical tryptophan in a position optimal for packing with the apolar face of galactose but incompatible with mannose binding. The 2-acetamido substituent of GalNAc is in the vicinity of amino acid positions identified by site-directed mutagenesis (Iobst, S. T., and Drickamer, K. (1996) J. Biol. Chem. 271, 6686-6693) as being important for the formation of a GalNAc-selective binding site.


==About this Structure==
Structural basis of galactose recognition by C-type animal lectins.,Kolatkar AR, Weis WI J Biol Chem. 1996 Mar 22;271(12):6679-85. PMID:8636086<ref>PMID:8636086</ref>
1AFB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with NGA, CA and CL as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1AFB OCA].


==Reference==
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
Structural basis of galactose recognition by C-type animal lectins., Kolatkar AR, Weis WI, J Biol Chem. 1996 Mar 22;271(12):6679-85. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8636086 8636086]
</div>
<div class="pdbe-citations 1afb" style="background-color:#fffaf0;"></div>
 
==See Also==
*[[Mannose-binding protein|Mannose-binding protein]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Rattus norvegicus]]
[[Category: Rattus norvegicus]]
[[Category: Single protein]]
[[Category: Kolatkar AR]]
[[Category: Kolatkar, A.R.]]
[[Category: Weis WI]]
[[Category: Weis, W.I.]]
[[Category: CA]]
[[Category: CL]]
[[Category: NGA]]
[[Category: c-type lectin]]
[[Category: calcium-binding protein]]
 
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