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== Function ==
== Function ==
[https://www.uniprot.org/uniprot/MVL_MICVR MVL_MICVR] Carbohydrate-binding protein that binds oligomannosides such as Man(6)GlcNAc(2) with sub-micromolar affinities. The specificity of MVL is unique in that its minimal target comprises the Man-alpha-(1->6)-Man-beta-(1->4)-GlcNAc-beta-(1->4)-GlcNAc tetrasaccharide core (Man(2)A) found in N-linked oligomannosides. Displays hemagglutininating activity on rabbit, horse and hen erythrocytes. This activity is inhibited by yeast mannan. Does not bind mono- and disachharides. Inhibits HIV-1 envelope-mediated cell fusion at nanomolar concentrations through carbohydrate-mediated interactions with high-mannose residues on the surface of the HIV envelope glycoprotein gp120.  Unexpectedly for a lectin, one of the 2 oligomannose binding sites of MVL can catalyze the cleavage of chitin fragments (such as chitotriose, i.e. GlcNAc(3) or GlcNAc-beta-(1->4)-GlcNAcbeta-(1->4)-GlcNAc, and chitotetraose, i.e. GlcNAc(4)) to GlcNAc. This weak glycosidase activity is restricted to the C-terminal carbohydrate-binding site. Does not cleave Man(3)GlcNAc(2) or the tetrasaccharide Man(2)A.
[https://www.uniprot.org/uniprot/MVL_MICVR MVL_MICVR] Carbohydrate-binding protein that binds oligomannosides such as Man(6)GlcNAc(2) with sub-micromolar affinities. The specificity of MVL is unique in that its minimal target comprises the Man-alpha-(1->6)-Man-beta-(1->4)-GlcNAc-beta-(1->4)-GlcNAc tetrasaccharide core (Man(2)A) found in N-linked oligomannosides. Displays hemagglutininating activity on rabbit, horse and hen erythrocytes. This activity is inhibited by yeast mannan. Does not bind mono- and disachharides. Inhibits HIV-1 envelope-mediated cell fusion at nanomolar concentrations through carbohydrate-mediated interactions with high-mannose residues on the surface of the HIV envelope glycoprotein gp120.  Unexpectedly for a lectin, one of the 2 oligomannose binding sites of MVL can catalyze the cleavage of chitin fragments (such as chitotriose, i.e. GlcNAc(3) or GlcNAc-beta-(1->4)-GlcNAcbeta-(1->4)-GlcNAc, and chitotetraose, i.e. GlcNAc(4)) to GlcNAc. This weak glycosidase activity is restricted to the C-terminal carbohydrate-binding site. Does not cleave Man(3)GlcNAc(2) or the tetrasaccharide Man(2)A.
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== Publication Abstract from PubMed ==
The cyanobacterial protein MVL inhibits HIV-1 envelope-mediated cell fusion at nanomolar concentrations by binding to high mannose N-linked carbohydrate on the surface of the envelope glycoprotein gp120. Although a number of other carbohydrate-binding proteins have been shown to inhibit HIV-1 envelope-mediated cell fusion, the specificity of MVL is unique in that its minimal target comprises the Man(alpha)(1--&gt;6)Man(beta)(1--&gt;4)GlcNAc(beta)(1--&gt;4)GlcNAc tetrasaccharide core of oligomannosides. We have solved the crystal structures of MVL free and bound to the pentasaccharide Man3GlcNAc2 at 1.9- and 1.8-A resolution, respectively. MVL is a homodimer stabilized by an extensive intermolecular interface between monomers. Each monomer contains two structurally homologous domains with high sequence similarity connected by a short five-amino acid residue linker. Intriguingly, a water-filled channel is observed between the two monomers. Residual dipolar coupling measurements indicate that the structure of the MVL dimer in solution is identical to that in the crystal. Man3GlcNAc2 binds to a preformed cleft at the distal end of each domain such that a total of four independent carbohydrate molecules associate with each homodimer. The binding cleft provides shape complementarity, including the presence of a deep hydrophobic hole that accommodates the N-acetyl methyl at the reducing end of the carbohydrate, and specificity arises from 7-8 intermolecular hydrogen bonds. The structures of MVL and the MVL-Man3GlcNAc2 complex further our understanding of the molecular basis of high affinity and specificity in protein-carbohydrate recognition.
Crystal structures of the HIV-1 inhibitory cyanobacterial protein MVL free and bound to Man3GlcNAc2: structural basis for specificity and high-affinity binding to the core pentasaccharide from n-linked oligomannoside.,Williams DC Jr, Lee JY, Cai M, Bewley CA, Clore GM J Biol Chem. 2005 Aug 12;280(32):29269-76. Epub 2005 Jun 3. PMID:15937331<ref>PMID:15937331</ref>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1zhs" style="background-color:#fffaf0;"></div>


==See Also==
==See Also==
*[[Mannose-binding protein|Mannose-binding protein]]
*[[Mannose-binding protein|Mannose-binding protein]]
== References ==
<references/>
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__TOC__
</StructureSection>
</StructureSection>

Latest revision as of 12:05, 14 February 2024

Crystal structure of MVL bound to Man3GlcNAc2Crystal structure of MVL bound to Man3GlcNAc2

Structural highlights

1zhs is a 8 chain structure with sequence from Microcystis viridis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.8Å
Ligands:, , , ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

MVL_MICVR Carbohydrate-binding protein that binds oligomannosides such as Man(6)GlcNAc(2) with sub-micromolar affinities. The specificity of MVL is unique in that its minimal target comprises the Man-alpha-(1->6)-Man-beta-(1->4)-GlcNAc-beta-(1->4)-GlcNAc tetrasaccharide core (Man(2)A) found in N-linked oligomannosides. Displays hemagglutininating activity on rabbit, horse and hen erythrocytes. This activity is inhibited by yeast mannan. Does not bind mono- and disachharides. Inhibits HIV-1 envelope-mediated cell fusion at nanomolar concentrations through carbohydrate-mediated interactions with high-mannose residues on the surface of the HIV envelope glycoprotein gp120. Unexpectedly for a lectin, one of the 2 oligomannose binding sites of MVL can catalyze the cleavage of chitin fragments (such as chitotriose, i.e. GlcNAc(3) or GlcNAc-beta-(1->4)-GlcNAcbeta-(1->4)-GlcNAc, and chitotetraose, i.e. GlcNAc(4)) to GlcNAc. This weak glycosidase activity is restricted to the C-terminal carbohydrate-binding site. Does not cleave Man(3)GlcNAc(2) or the tetrasaccharide Man(2)A.

See Also

1zhs, resolution 1.80Å

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