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PDBsum entry 3frp
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Hydrolase cofactor
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PDB id
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3frp
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Contents |
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602 a.a.
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215 a.a.
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343 a.a.
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References listed in PDB file
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Key reference
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Title
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The crystal structure of cobra venom factor, A cofactor for c3- And c5-Convertase cvfbb.
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Authors
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V.Krishnan,
K.Ponnuraj,
Y.Xu,
K.Macon,
J.E.Volanakis,
S.V.Narayana.
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Ref.
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Structure, 2009,
17,
611-619.
[DOI no: ]
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PubMed id
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Abstract
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Cobra venom factor (CVF) is a functional analog of human complement component
C3b, the active fragment of C3. Similar to C3b, in human and mammalian serum,
CVF binds factor B, which is then cleaved by factor D, giving rise to the CVFBb
complex that targets the same scissile bond in C3 as the authentic complement
convertases C4bC2a and C3bBb. Unlike the latter, CVFBb is a stable complex and
an efficient C5 convertase. We solved the crystal structure of CVF, isolated
from Naja naja kouthia venom, at 2.6 A resolution. The CVF crystal structure, an
intermediate between C3b and C3c, lacks the TED domain and has the CUB domain in
an identical position to that seen in C3b. The similarly positioned CUB and
slightly displaced C345c domains of CVF could play a vital role in the formation
of C3 convertases by providing important primary binding sites for factor B.
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Figure 3.
Figure 3. Comparison of CVF with C3c and C3b Structures
(A) Ribbon diagrams of C3c (left), CVF (middle), and C3b
(right). C3c and C3b are made of two chains, β (green) and α
(red), whereas CVF is composed of three chains, α (yellow), β
(magenta), and γ (cyan).
(B) Schematic depiction of domain
organizations of C3c, CVF, and C3b (colored according to chains
as in the ribbon in (A).
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Figure 5.
Figure 5. Proposed Factor B Binding Sites
These sites
are indicated (in gold) on the structure of CVF (only the top
half of the molecule is shown). The small panel depicts the CVF
site α'NT (gold) in comparison with the corresponding sites of
C3b (green) and C3c (red).
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The above figures are
reprinted
by permission from Cell Press:
Structure
(2009,
17,
611-619)
copyright 2009.
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