1bzq
From Proteopedia
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| - | [[Image:1bzq.jpg|left|200px]] | + | [[Image:1bzq.jpg|left|200px]] |
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| - | '''COMPLEX OF A DROMEDARY SINGLE-DOMAIN VHH ANTIBODY FRAGMENT WITH RNASE A''' | + | {{Structure |
| + | |PDB= 1bzq |SIZE=350|CAPTION= <scene name='initialview01'>1bzq</scene>, resolution 2.8Å | ||
| + | |SITE= | ||
| + | |LIGAND= <scene name='pdbligand=PO4:PHOSPHATE ION'>PO4</scene> | ||
| + | |ACTIVITY= [http://en.wikipedia.org/wiki/Pancreatic_ribonuclease Pancreatic ribonuclease], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.27.5 3.1.27.5] | ||
| + | |GENE= | ||
| + | }} | ||
| + | |||
| + | '''COMPLEX OF A DROMEDARY SINGLE-DOMAIN VHH ANTIBODY FRAGMENT WITH RNASE A''' | ||
| + | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1BZQ is a [ | + | 1BZQ is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] and [http://en.wikipedia.org/wiki/Camelus_dromedarius Camelus dromedarius]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BZQ OCA]. |
==Reference== | ==Reference== | ||
| - | A single-domain antibody fragment in complex with RNase A: non-canonical loop structures and nanomolar affinity using two CDR loops., Decanniere K, Desmyter A, Lauwereys M, Ghahroudi MA, Muyldermans S, Wyns L, Structure. 1999 Apr 15;7(4):361-70. PMID:[http:// | + | A single-domain antibody fragment in complex with RNase A: non-canonical loop structures and nanomolar affinity using two CDR loops., Decanniere K, Desmyter A, Lauwereys M, Ghahroudi MA, Muyldermans S, Wyns L, Structure. 1999 Apr 15;7(4):361-70. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/10196124 10196124] |
[[Category: Bos taurus]] | [[Category: Bos taurus]] | ||
[[Category: Camelus dromedarius]] | [[Category: Camelus dromedarius]] | ||
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[[Category: ribonuclease]] | [[Category: ribonuclease]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 10:18:01 2008'' |
Revision as of 08:18, 20 March 2008
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| , resolution 2.8Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | |||||||
| Activity: | Pancreatic ribonuclease, with EC number 3.1.27.5 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
COMPLEX OF A DROMEDARY SINGLE-DOMAIN VHH ANTIBODY FRAGMENT WITH RNASE A
Overview
BACKGROUND: Camelid serum contains a large fraction of functional heavy-chain antibodies - homodimers of heavy chains without light chains. The variable domains of these heavy-chain antibodies (VHH) have a long complementarity determining region 3 (CDR3) loop that compensates for the absence of the antigen-binding loops of the variable light chains (VL). In the case of the VHH fragment cAb-Lys3, part of the 24 amino acid long CDR3 loop protrudes from the antigen-binding surface and inserts into the active-site cleft of its antigen, rendering cAb-Lys3 a competitive enzyme inhibitor. RESULTS: A dromedary VHH with specificity for bovine RNase A, cAb-RN05, has a short CDR3 loop of 12 amino acids and is not a competitive enzyme inhibitor. The structure of the cAb-RN05-RNase A complex has been solved at 2.8 A. The VHH scaffold architecture is close to that of a human VH (variable heavy chain). The structure of the antigen-binding hypervariable 1 loop (H1) of both cAb-RN05 and cAb-Lys3 differ from the known canonical structures; in addition these H1 loops resemble each other. The CDR3 provides an antigen-binding surface and shields the face of the domain that interacts with VL in conventional antibodies. CONCLUSIONS: VHHs adopt the common immunoglobulin fold of variable domains, but the antigen-binding loops deviate from the predicted canonical structure. We define a new canonical structure for the H1 loop of immunoglobulins, with cAb-RN05 and cAb-Lys3 as reference structures. This new loop structure might also occur in human or mouse VH domains. Surprisingly, only two loops are involved in antigen recognition; the CDR2 does not participate. Nevertheless, the antigen binding occurs with nanomolar affinities because of a preferential usage of mainchain atoms for antigen interaction.
About this Structure
1BZQ is a Single protein structure of sequence from Bos taurus and Camelus dromedarius. Full crystallographic information is available from OCA.
Reference
A single-domain antibody fragment in complex with RNase A: non-canonical loop structures and nanomolar affinity using two CDR loops., Decanniere K, Desmyter A, Lauwereys M, Ghahroudi MA, Muyldermans S, Wyns L, Structure. 1999 Apr 15;7(4):361-70. PMID:10196124
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