Crystal structure of the ectodomain of human FcalphaRI.
Human FcalphaRI (CD89) is the receptor specific for IgA, an immunoglobulin that is abundant in mucosa and is also found in high concentrations in serum. Although FcalphaRI is an immunoglobulin Fc receptor (FcR), it differs in many ways from FcRs for other immunoglobulin classes. The genes of most FcRs are located on chromosome 1 at 1q21-23, whereas FcalphaRI is on chromosome 19, at 19q13.4, a region called the leukocyte receptor complex, because it is clustered with several leukocyte receptor families including killer cell inhibitory receptors (KIRs) and leukocyte Ig-like receptors (LIRs). The amino acid sequence of FcalphaRI shares only 20% homology with other FcRs but it has around 35% homology with its neighboring LIRs and KIRs. In this work, we analyzed the crystal structure of the ectodomain of FcalphaRI and examined structure similarities between FcalphaRI and KIR2DL1, KIR2DL2 and LIR-1. Our data show that FcalphaRI, KIRs, and LIRs share a common hydrophobic core in their interdomain interface, and FcalphaRI is evolutionally closer to LIR than KIR.
Ding
Yi
Y
Ministry of Education Protein Science Laboratory & Laboratory of Structural Biology, Tsinghua University, Beijing, 100084, China.
Xu
Gang
G
Yang
Maojun
M
Yao
Min
M
Gao
George F
GF
Wang
Linfang
L
Zhang
Wei
W
Rao
Zihe
Z
D000595:Amino Acid Sequence; D015703:Antigens, CD / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004220:Disulfides / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D007070:Immunoglobulin A / Q000737:chemistry; D007074:Immunoglobulin G / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000737:chemistry; D011961:Receptors, Fc / Q000737:chemistry*; D011971:Receptors, Immunologic / Q000737:chemistry; D017386:Sequence Homology, Amino Acid
D015703:Antigens, CD; D004220:Disulfides; C036832:Fc(alpha) receptor; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D011956:Receptors, Cell Surface; D011961:Receptors, Fc; D011971:Receptors, Immunologic