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Mapping the active site of CD59.

Yu J, Abagyan R, Dong S, Gilbert A, Nussenzweig V, Tomlinson S - J. Exp. Med. (1997)

Bottom Line: CD59 is a widely distributed membrane-bound inhibitor of the cytolytic membrane attack complex (MAC) of complement.We present data obtained from a combination of molecular modeling and mutagenesis techniques, which together indicate that the active site of CD59 is located in the vicinity of a hydrophobic groove on the face of the molecule opposite to a "hydrophobic strip" suggested earlier.In addition, removal of the single N-linked glycosylation site at Asn18 of CD59 resulted in an enhancement of complement inhibitory activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, New York University Medical Center, New York 10016, USA.

ABSTRACT
CD59 is a widely distributed membrane-bound inhibitor of the cytolytic membrane attack complex (MAC) of complement. This small (77 amino acid) glycoprotein is a member of the Ly6 superfamily of proteins and is important in protecting host cells from the lytic and proinflammatory activity of the MAC. CD59 functions by binding to C8 and/or C9 in the nascent MAC and interfering with C9 membrane insertion and polymerization. We present data obtained from a combination of molecular modeling and mutagenesis techniques, which together indicate that the active site of CD59 is located in the vicinity of a hydrophobic groove on the face of the molecule opposite to a "hydrophobic strip" suggested earlier. In addition, removal of the single N-linked glycosylation site at Asn18 of CD59 resulted in an enhancement of complement inhibitory activity.

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Related in: MedlinePlus

Diagram of CD59. (a) Ribbon diagram (1). Conserved residues (Tyr36, Trp40, and Leu54) and Phe23 (always hydrophobic) which  were mutated for functional studies are shown. The two fragments of the  protein (1-16 and 57-77) that can be replaced with Ly6E sequence without affecting function are shown by yellow ribbon. (b) Molecular surface  of CD59. The exposed surface patches of all of the evolutionary conserved residues that occur between positions 16-57 on the displayed face  of the molecules are shown (green patches). Conserved residue classes are  shown in blue (refer to text for details). The colored patches represent the  molecular surface of the side chains of conserved residues and residue  classes.
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Figure 7: Diagram of CD59. (a) Ribbon diagram (1). Conserved residues (Tyr36, Trp40, and Leu54) and Phe23 (always hydrophobic) which were mutated for functional studies are shown. The two fragments of the protein (1-16 and 57-77) that can be replaced with Ly6E sequence without affecting function are shown by yellow ribbon. (b) Molecular surface of CD59. The exposed surface patches of all of the evolutionary conserved residues that occur between positions 16-57 on the displayed face of the molecules are shown (green patches). Conserved residue classes are shown in blue (refer to text for details). The colored patches represent the molecular surface of the side chains of conserved residues and residue classes.

Mentions: To reveal the hypothetical location and extent of the functional site, we built a model of the molecular surface of CD59 and analyzed: (a) the three-dimensional location of the fragments that can be replaced by the Ly6E fragments, (b) the distribution of surface patches that are conserved between CD59 of seven different species that are either closely related to human, or that have been shown to inhibit human complement (Fig. 6), and finally, (c) the surface shape. A very clear picture emerged from this analysis. Fig. 7 a displays the molecule in an orientation that shows that the regions of CD59 that can be replaced by Ly6E without loss of function (1-16 and 57-77) are located at the backside of the molecule (in yellow, Fig. 7 a). From the position of residue 77, to which the GPI membrane anchor is attached, it can be predicted that the active site is located on the exposed face of the molecule.


Mapping the active site of CD59.

Yu J, Abagyan R, Dong S, Gilbert A, Nussenzweig V, Tomlinson S - J. Exp. Med. (1997)

Diagram of CD59. (a) Ribbon diagram (1). Conserved residues (Tyr36, Trp40, and Leu54) and Phe23 (always hydrophobic) which  were mutated for functional studies are shown. The two fragments of the  protein (1-16 and 57-77) that can be replaced with Ly6E sequence without affecting function are shown by yellow ribbon. (b) Molecular surface  of CD59. The exposed surface patches of all of the evolutionary conserved residues that occur between positions 16-57 on the displayed face  of the molecules are shown (green patches). Conserved residue classes are  shown in blue (refer to text for details). The colored patches represent the  molecular surface of the side chains of conserved residues and residue  classes.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196154&req=5

Figure 7: Diagram of CD59. (a) Ribbon diagram (1). Conserved residues (Tyr36, Trp40, and Leu54) and Phe23 (always hydrophobic) which were mutated for functional studies are shown. The two fragments of the protein (1-16 and 57-77) that can be replaced with Ly6E sequence without affecting function are shown by yellow ribbon. (b) Molecular surface of CD59. The exposed surface patches of all of the evolutionary conserved residues that occur between positions 16-57 on the displayed face of the molecules are shown (green patches). Conserved residue classes are shown in blue (refer to text for details). The colored patches represent the molecular surface of the side chains of conserved residues and residue classes.
Mentions: To reveal the hypothetical location and extent of the functional site, we built a model of the molecular surface of CD59 and analyzed: (a) the three-dimensional location of the fragments that can be replaced by the Ly6E fragments, (b) the distribution of surface patches that are conserved between CD59 of seven different species that are either closely related to human, or that have been shown to inhibit human complement (Fig. 6), and finally, (c) the surface shape. A very clear picture emerged from this analysis. Fig. 7 a displays the molecule in an orientation that shows that the regions of CD59 that can be replaced by Ly6E without loss of function (1-16 and 57-77) are located at the backside of the molecule (in yellow, Fig. 7 a). From the position of residue 77, to which the GPI membrane anchor is attached, it can be predicted that the active site is located on the exposed face of the molecule.

Bottom Line: CD59 is a widely distributed membrane-bound inhibitor of the cytolytic membrane attack complex (MAC) of complement.We present data obtained from a combination of molecular modeling and mutagenesis techniques, which together indicate that the active site of CD59 is located in the vicinity of a hydrophobic groove on the face of the molecule opposite to a "hydrophobic strip" suggested earlier.In addition, removal of the single N-linked glycosylation site at Asn18 of CD59 resulted in an enhancement of complement inhibitory activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, New York University Medical Center, New York 10016, USA.

ABSTRACT
CD59 is a widely distributed membrane-bound inhibitor of the cytolytic membrane attack complex (MAC) of complement. This small (77 amino acid) glycoprotein is a member of the Ly6 superfamily of proteins and is important in protecting host cells from the lytic and proinflammatory activity of the MAC. CD59 functions by binding to C8 and/or C9 in the nascent MAC and interfering with C9 membrane insertion and polymerization. We present data obtained from a combination of molecular modeling and mutagenesis techniques, which together indicate that the active site of CD59 is located in the vicinity of a hydrophobic groove on the face of the molecule opposite to a "hydrophobic strip" suggested earlier. In addition, removal of the single N-linked glycosylation site at Asn18 of CD59 resulted in an enhancement of complement inhibitory activity.

Show MeSH
Related in: MedlinePlus