Complete amino acid sequence and homologies of human erythrocyte membrane protein band 4.2
| Autor: | David W. Speicher, Stephen Lambert, Jack Lawler, Carl M. Cohen, Catherine Korsgren |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Reticulocytes
Molecular Sequence Data Restriction Mapping Sequence alignment Biology Sequence Homology Nucleic Acid Complementary DNA Animals Humans Amino Acid Sequence Peptide sequence Gene Library chemistry.chemical_classification Alanine Multidisciplinary Base Sequence Nucleic acid sequence Protein primary structure Membrane Proteins Blood Proteins DNA Molecular biology Amino acid Cytoskeletal Proteins chemistry Biochemistry Research Article Plasmids Cysteine |
| Zdroj: | Proceedings of the National Academy of Sciences. 87:613-617 |
| ISSN: | 1091-6490 0027-8424 |
| Popis: | The complete amino acid sequence for human erythrocyte band 4.2 has been derived from the nucleotide sequence of a full-length 2.35-kilobase (kb) cDNA. The 2.35-kb cDNA was isolated from a human reticulocyte cDNA library made in the expression vector lambda gt11. Of the 2348 base pairs (bp), 2073 bp encode 691 amino acids representing 76.9 kDa (the SDS/PAGE molecular mass is 72 kDa). RNA blot analysis of human reticulocyte total RNA gives a message size for band 4.2 of 2.4 kb. The amino acid sequence of band 4.2 has homology with two closely related Ca2(+)-dependent cross-linking proteins, guinea pig liver transglutaminase (protein-glutamine gamma-glutamyltransferase; protein-glutamine: amine gamma-glutamyltransferase, EC 2.3.2.13) (32% identity in a 446-amino acid overlap) and the a subunit of human coagulation factor XIII (27% identity in a 639-amino acid overlap), a transglutaminase that forms intermolecular gamma-glutamyl-epsilon-lysine bonds between fibrin molecules. The region of greatest identity includes a 49-amino acid stretch of band 4.2, which is 69% and 51% identical with guinea pig liver transglutaminase and the a subunit of factor XIII, respectively, within the regions that contain the active sites of these enzymes. Significantly, within the five contiguous consensus residues of the transglutaminase active site, Gly-Gln-Cys-Trp-Val, band 4.2 has an alanine substituted for cysteine (which is apparently essential for activity). Consistent with this active site substitution, erythrocyte membranes or inside-out vesicles, which contain band 4.2, show no evidence of transglutaminase activity by two types of in vitro assay. |
| Databáze: | OpenAIRE |
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