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[[Image: | ==STRUCTURAL EVIDENCE FOR A PH-SENSITIVE DI-LYSINE TRIGGER IN THE HEN OVOTRANSFERRIN N-LOBE: IMPLICATIONS FOR TRANSFERRIN IRON RELEASE== | ||
<StructureSection load='1nnt' size='340' side='right' caption='[[1nnt]], [[Resolution|resolution]] 2.30Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1nnt]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NNT OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1NNT FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CO3:CARBONATE+ION'>CO3</scene>, <scene name='pdbligand=FE:FE+(III)+ION'>FE</scene><br> | |||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1nnt FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1nnt OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1nnt RCSB], [http://www.ebi.ac.uk/pdbsum/1nnt PDBsum]</span></td></tr> | |||
<table> | |||
== 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/nn/1nnt_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.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/chain_selection.php?pdb_ID=2ata ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Members of the transferrin family of proteins are involved in Fe3+ transport (serum transferrins) and are also believed to possess antimicrobial activity (ovotransferrins and lactoferrins). The structure of the monoferric N-terminal half-molecule of hen ovotransferrin, reported here at 2.3-A resolution, reveals an unusual interdomain interaction formed between the side-chain NZ atoms of Lys 209 and Lys 301, which are 2.3 A apart. This strong interaction appears to be an example of a low-barrier hydrogen bond between the two lysine NZ atoms, both of which are also involved in a hydrogen-bonding interaction with the aromatic ring of a tyrosine residue. Crystals of the protein were grown at pH 5.9, which is well below the usual pKa approximately 10 for a lysine side chain. We suggest that the pKa of either one or both of these residues lies below the pH of the structure determination and is, therefore, not positively charged. This finding may serve to explain, on a molecular basis, the pH dependence of transferrin Fe3+ release. We propose that uptake of the Fe(3+)-transferrin complex into an acidic endosome (viz., pH approximately 5.0) via receptor-mediated endocytosis will result in the protonation of both lysine residues. The close proximity of the two resulting positive charges, and their location on opposite domains of the N-lobe, might well be the driving force that opens the two domains of the protein, exposing the Fe3+ ion and facilitating its release.(ABSTRACT TRUNCATED AT 250 WORDS) | |||
Structural evidence for a pH-sensitive dilysine trigger in the hen ovotransferrin N-lobe: implications for transferrin iron release.,Dewan JC, Mikami B, Hirose M, Sacchettini JC Biochemistry. 1993 Nov 16;32(45):11963-8. PMID:8218271<ref>PMID:8218271</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | ==See Also== | ||
*[[Transferrin|Transferrin]] | *[[Transferrin|Transferrin]] | ||
== References == | |||
== | <references/> | ||
< | __TOC__ | ||
</StructureSection> | |||
[[Category: Gallus gallus]] | [[Category: Gallus gallus]] | ||
[[Category: Dewan, J C.]] | [[Category: Dewan, J C.]] | ||
Revision as of 20:16, 28 September 2014
STRUCTURAL EVIDENCE FOR A PH-SENSITIVE DI-LYSINE TRIGGER IN THE HEN OVOTRANSFERRIN N-LOBE: IMPLICATIONS FOR TRANSFERRIN IRON RELEASESTRUCTURAL EVIDENCE FOR A PH-SENSITIVE DI-LYSINE TRIGGER IN THE HEN OVOTRANSFERRIN N-LOBE: IMPLICATIONS FOR TRANSFERRIN IRON RELEASE
Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedMembers of the transferrin family of proteins are involved in Fe3+ transport (serum transferrins) and are also believed to possess antimicrobial activity (ovotransferrins and lactoferrins). The structure of the monoferric N-terminal half-molecule of hen ovotransferrin, reported here at 2.3-A resolution, reveals an unusual interdomain interaction formed between the side-chain NZ atoms of Lys 209 and Lys 301, which are 2.3 A apart. This strong interaction appears to be an example of a low-barrier hydrogen bond between the two lysine NZ atoms, both of which are also involved in a hydrogen-bonding interaction with the aromatic ring of a tyrosine residue. Crystals of the protein were grown at pH 5.9, which is well below the usual pKa approximately 10 for a lysine side chain. We suggest that the pKa of either one or both of these residues lies below the pH of the structure determination and is, therefore, not positively charged. This finding may serve to explain, on a molecular basis, the pH dependence of transferrin Fe3+ release. We propose that uptake of the Fe(3+)-transferrin complex into an acidic endosome (viz., pH approximately 5.0) via receptor-mediated endocytosis will result in the protonation of both lysine residues. The close proximity of the two resulting positive charges, and their location on opposite domains of the N-lobe, might well be the driving force that opens the two domains of the protein, exposing the Fe3+ ion and facilitating its release.(ABSTRACT TRUNCATED AT 250 WORDS) Structural evidence for a pH-sensitive dilysine trigger in the hen ovotransferrin N-lobe: implications for transferrin iron release.,Dewan JC, Mikami B, Hirose M, Sacchettini JC Biochemistry. 1993 Nov 16;32(45):11963-8. PMID:8218271[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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