Molecular cloning of a human serum protein structurally related to complement factor H.
Two cDNA clones termed H36-1 and H36-2 were isolated from a human liver cDNA library. Clone H36-1 appears to represent the recently isolated human serum proteins h37 and h42, which are two differently glycosylated forms of a protein antigenically related to human complement factor H. The H36-1 deduced protein sequence is 327 amino acid long and possesses a leader sequence. The secreted part of the protein is comprised of five tandem repeating units, termed short consensus repeats (SCRs). SCR 1 and 2 display high homology to the corresponding region of the recently isolated murine factor H-related cDNA clone 13G1. In contrast, the 3'-end of the H36-1 clone shows sequence homology to the 3'-end of human complement factor H. The second clone, H36-2, is nearly identical to H36-1. Within 1148 base pairs, where the two clones overlap, their nucleotide sequences differed at nine positions. One nucleotide exchange in the sequence of H36-2 which was located within SCR 1 creats a stop codon (TAA). Consequently, the corresponding mRNA cannot code for a functional protein, suggesting that this clone is a transcribed pseudogene. These two clones represent new human members of the family of proteins structurally related to complement factor H.
Skerka
C
C
Bernhard Nocht Institute for Tropical Medicine, Hamburg, Federal Republic of Germany.
Horstmann
R D
RD
Zipfel
P F
PF
D000595:Amino Acid Sequence; D001483:Base Sequence; D001798:Blood Proteins / Q000235:genetics*; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D003180:Complement C3b Inactivator Proteins / Q000235:genetics*; D017242:Complement Factor H; D004247:DNA / Q000235:genetics; D006031:Glycosylation; D006801:Humans; D008099:Liver / Q000737:chemistry; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes; D012313:RNA / Q000032:analysis; D012091:Repetitive Sequences, Nucleic Acid; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid
D001798:Blood Proteins; C493495:CFH protein, human; D003180:Complement C3b Inactivator Proteins; D015345:Oligonucleotide Probes; D012313:RNA; D017242:Complement Factor H; D004247:DNA