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PDBsum entry 1a4j
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Immunoglobulin
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PDB id
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1a4j
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Immunological origins of binding and catalysis in a diels-Alderase antibody.
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Authors
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F.E.Romesberg,
B.Spiller,
P.G.Schultz,
R.C.Stevens.
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Ref.
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Science, 1998,
279,
1929-1933.
[DOI no: ]
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PubMed id
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Abstract
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The three-dimensional structure of an antibody (39-A11) that catalyzes a
Diels-Alder reaction has been determined. The structure suggests that the
antibody catalyzes this pericyclic reaction through a combination of packing and
hydrogen-bonding interactions that control the relative geometries of the bound
substrates and electronic distribution in the dienophile. A single somatic
mutation, serine-91 of the light chain to valine, is largely responsible for the
increase in affinity and catalytic activity of the affinity-matured antibody.
Structural and functional studies of the germ-line precursor suggest that 39-A11
and related antibodies derive from a family of germ-line genes that have been
selected throughout evolution for the ability of the encoded proteins to form a
polyspecific combining site. Germ line-encoded antibodies of this type, which
can rapidly evolve into high-affinity receptors for a broad range of structures,
may help to expand the binding potential associated with the structural
diversity of the primary antibody repertoire.
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Figure 3.
Fig. 3. Structures of ligands used in binding assays with
39-A11 and its germ-line precursor.
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Figure 4.
Fig. 4. Superposition of the CDRL3 and CDRH3 loops of
antibodies DB3, TE33, and 39-A11 with bound steroid (green),
peptide (blue), and hapten 4 (purple), respectively. TrpH50,
Asn/SerH35, and Trp/ArgH100 are also shown.
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The above figures are
reprinted
by permission from the AAAs:
Science
(1998,
279,
1929-1933)
copyright 1998.
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