Sequence analysis and chromosomal localization of human Cap Z. Conserved residues within the actin-binding domain may link Cap Z to gelsolin/severin and profilin protein families
| Autor: | E A, Barron-Casella, M A, Torres, S W, Scherer, H H, Heng, L C, Tsui, J F, Casella |
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| Rok vydání: | 1995 |
| Předmět: |
Macromolecular Substances
Molecular Sequence Data Muscle Proteins Saccharomyces cerevisiae Protein Structure Secondary Retina Mice Animals Humans Dictyostelium Amino Acid Sequence Caenorhabditis elegans Chromosomes Artificial Yeast Genes Immediate-Early Conserved Sequence DNA Primers Gene Library CapZ Actin Capping Protein Binding Sites Base Sequence Sequence Homology Amino Acid Microfilament Proteins Chromosome Mapping Hominidae Actins Recombinant Proteins Chromosomes Human Pair 1 Chickens Chromosomes Human Pair 7 |
| Zdroj: | The Journal of biological chemistry. 270(37) |
| ISSN: | 0021-9258 |
| Popis: | From a human retinal cDNA library, we have isolated cDNAs that are homologs for the alpha 2 and beta subunits of chicken Cap Z. The derived human alpha subunit shares 95% amino acid identity with the chicken alpha 2 subunit; the beta subunit is 99% identical to the chicken subunit residues 1-243. The remaining portion of the human beta subunit (244-272) diverges significantly with only 8 out of 29 C-terminal amino acids conserved between the two species. This lack of conservation is of particular interest because the chicken C terminus contains an actin-binding domain. Cosedimentation assays with F-actin show that human Cap Z binds actin with an affinity equal that of chicken Cap Z. These results point to the eight shared amino acids as critical for actin binding, three of which are regularly spaced leucines. These apolar residues and one outside the region of divergence align well with those residues of the actin-binding alpha-helix proposed for gelsolin segment 1. The apolar residues as well as three polar amino acids are also conserved in other capping, capping and severing, and monomer-binding proteins. Amino acid substitutions in the chicken beta subunit of the two most highly conserved leucines result in significant decreases in F-actin binding activity. The human alpha 2 gene (CAPZA2) has been mapped to chromosome 7 position q31.2-q31.3 and the beta gene (CAPZB) to chromosome 1 region p36.1. |
| Databáze: | OpenAIRE |
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