ISSN:
1432-2048
Schlagwort(e):
Ca2+ -ATPase
;
Calcium-homeostasis
;
Dunaliella
;
Endoplasmic reticulum
;
P-type ATPase
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract We have determined the complete primary structure of a putative P-type Ca2+ -ATPase from the unicellular, halotolerant alga Dunaliella bioculata. The protein (DBCA1) with a calculated molecular mass of 114 kDa and eight or ten putative transmembrane segments contains all amino acid motifs specific to the family of P-type ATPases. Highest homology scores were obtained by comparison with (sarco)endoplasmic reticulum-type plant and animal Ca2+-ATPases (54% identity, 70% similarity). In addition, all amino acids shown to be essential for Ca2+ transport in animal sarcoplasmic reticulum Ca2+-ATPases are preserved in DBCA1. Significantly lower homologies were found with animal plasma membrane Ca2+-ATPases (33% identity, 55% similarity), and the carboxyterminus of DBCA1 gave no indications of possible calmodulin-binding sites, characteristic of those enzymes. It is assumed that DBCA1 is a representative of the endomembrane class of Ca2+ ATPases. In Northern blot experiments with polyadenylated RNA, a 3.7-kb transcript was detected at levels which were very low compared with those of the plasma membrane H+-ATPase from D. bioculata (DBPMA1; Wolf et al., 1995, Plant Mol Biol 28: 657–666). Southern blot analyses suggest the existence of additional Ca2+-ATPase genes in the haploid genome of D. bioculata.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00196652
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