Chemokines (chemotactic cytokines) comprise a large family of proteins that
recruit and activate leukocytes, giving chemokines a major role in both immune response
and inflammation-related diseases. Viral CC chemokine inhibitor (vCCI) is a poxvirus
encoded protein that has been shown to bind tightly and inhibit the action of many CC
chemokines. This function suggests that vCCI could be explored as an antiinflammatory
therapeutic, a possibility that has been supported in mouse studies. The
structure of vCCI in unbound form was determined by others, but to date no structure
has been reported of bound vCCI. We report the NMR structure of vCCI in complex
with the human CC chemokine MIP-1[beta]. The non-aggregating MIP-1[beta] variant MIP-1[beta]
45AASA48 was used in this complex to allow sufficiently high concentration at pH 7 to
carry out the solution structure determination. A combination of NOE distance
restraints, torsion angle restraints, and residual dipolar coupling were used to determine
the structure of the complex, which also required protein deuteration due to its relatively
large size (34kDa). The structure shows that MIP-1[beta] binds to vCCI with 1:1 stoichiometry, forming a complex of 311 amino acids. vCCI uses residues from its [beta]-
sheet II to interact with a surface of MIP-1[beta] that includes residues adjacent to its Nterminus,
as well as residues in the 20's region, and the 40's loop. The structure of the
MIP-1[beta]-vCCI complex reveals for the first time the regions of each protein involved in
the interaction, and allows a greater understanding of the strategy used by vCCI to
tightly bind numerous chemokines, while retaining selectivity for the CC chemokine
subfamily.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/85901 |
| Date | 10 October 2008 |
| Creators | Zhang, Li |
| Contributors | LiWang, Patricia J. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation, text |
| Format | electronic, born digital |
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