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ABSTRACT: 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. The poxvirus-encoded viral CC chemokine inhibitor (vCCI) binds to many CC chemokines with high affinity, acting as a potent inhibitor of chemokine action. We have used heteronuclear multidimensional NMR to determine the structure of an orthopoxvirus vCCI in complex with a human CC chemokine, MIP-1beta (macrophage inflammatory protein 1beta). vCCI binds to the chemokine with 1:1 stoichiometry, forming a complex of 311 aa. vCCI uses residues from its beta-sheet II to interact with a surface of MIP-1beta that includes residues adjacent to its N terminus, as well as residues in the 20's region and the 40's loop. This structure reveals the strategy used by vCCI to tightly bind numerous chemokines while retaining selectivity for the CC chemokine subfamily.
Proceedings of the National Academy of Sciences 10/2006; 103(38):13985-90. · 9.68 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: 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. The poxvirus-encoded viral CC chemokine inhibitor
(vCCI) binds to many CC chemokines with high affinity, acting as a potent inhibitor of chemokine action. We have used heteronuclear
multidimensional NMR to determine the structure of an orthopoxvirus vCCI in complex with a human CC chemokine, MIP-1β (macrophage
inflammatory protein 1β). vCCI binds to the chemokine with 1:1 stoichiometry, forming a complex of 311 aa. vCCI uses residues
from its β-sheet II to interact with a surface of MIP-1β that includes residues adjacent to its N terminus, as well as residues
in the 20′s region and the 40′s loop. This structure reveals the strategy used by vCCI to tightly bind numerous chemokines
while retaining selectivity for the CC chemokine subfamily.
Proceedings of the National Academy of Sciences 09/2006; 103(38):13985-13990. · 9.68 Impact Factor
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ABSTRACT: MIP-1beta is a CC-chemokine that plays a role in inflammation and host defense mechanisms by interacting with its specific receptor CCR5. CCR5 is a major coreceptor for macrophage-tropic human immunodeficiency virus (HIV), and as a consequence, MIP-1beta can inhibit HIV entry. It is therefore of interest to understand how MIP-1beta and other CCR5 ligands bind to their receptor, as such understanding could lead to the rational design of more efficient HIV entry blockers. We have previously demonstrated the importance of Phe13, and of basic residues of the 40's loop, in mediating high-affinity binding of MIP-1beta to CCR5. We have now investigated further the relative contribution of other MIP-1beta residues in the interaction of the chemokine with CCR5, by studying the functional consequences of point mutations within the N-loop and the 3(10) turn of MIP-1beta, affecting the charge, size, and H-bonding properties of the side chains. Our data suggest that, in addition to Phe13, three amino acids of the N-loop and 3(10) turn (Arg18, Lys19, and Arg22) interact with CCR5 through their positive charge. We also found that Pro21 contributes to the CCR5 binding properties of MIP-1beta. Moreover, NMR spectroscopy has revealed that the presence of Tyr at position 15 is necessary for the proper folding of the chemokine. Our results therefore demonstrate that the binding determinants of MIP-1beta consist of residues arranged on one surface of the protein, including most of the basic residues in MIP-1beta, as well as two key hydrophobic groups. The good correlation observed between the potency of the mutants in a functional assay and their binding affinity strongly argues that basic residues Arg18, Lys19, and Arg22 of MIP-1beta are essential for its CCR5 binding properties, without a primary effect on CCR5 activation.
Biochemistry 12/2002; 41(46):13548-55. · 3.42 Impact Factor
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ABSTRACT: MIP-1‚ is a CC-chemokine that plays a role in inflammation and host defense mechanisms by interacting with its specific receptor CCR5. CCR5 is a major coreceptor for macrophage-tropic human immunodeficiency virus (HIV), and as a consequence, MIP-1‚ can inhibit HIV entry. It is therefore of interest to understand how MIP-1‚ and other CCR5 ligands bind to their receptor, as such understanding could lead to the rational design of more efficient HIV entry blockers. We have previously demonstrated the importance of Phe13, and of basic residues of the 40's loop, in mediating high-affinity binding of MIP-1‚ to CCR5. We have now investigated further the relative contribution of other MIP-1‚ residues in the interaction of the chemokine with CCR5, by studying the functional consequences of point mutations within the N-loop and the 310 turn of MIP-1‚, affecting the charge, size, and H-bonding properties of the side chains. Our data suggest that, in addition to Phe13, three amino acids of the N-loop and 3 10 turn (Arg18, Lys19, and Arg22) interact with CCR5 through their positive charge. We also found that Pro21 contributes to the CCR5 binding properties of MIP-1‚. Moreover, NMR spectroscopy has revealed that the presence of Tyr at position 15 is necessary for the proper folding of the chemokine. Our results therefore demonstrate that the binding determinants of MIP-1‚ consist of residues arranged on one surface of the protein, including most of the basic residues in MIP-1‚, as well as two key hydrophobic groups. The good correlation observed between the potency of the mutants in a functional assay and their binding affinity strongly argues that basic residues Arg18, Lys19, and Arg22 of MIP-1‚ are essential for its CCR5 binding properties, without a primary effect on CCR5 activation.
Biochemistry - BIOCHEMISTRY-USA. 01/2002; 41(46):13548-13555.
