3SLS_DENPO
ID 3SLS_DENPO Reviewed; 60 AA.
AC P22947;
DT 01-AUG-1991, integrated into UniProtKB/Swiss-Prot.
DT 01-AUG-1991, sequence version 1.
DT 25-MAY-2022, entry version 85.
DE RecName: Full=Calciseptin;
DE AltName: Full=Calciseptine;
DE Short=CaS;
DE AltName: Full=L-type calcium channel blocker;
OS Dendroaspis polylepis polylepis (Black mamba).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC Serpentes; Colubroidea; Elapidae; Elapinae; Dendroaspis.
OX NCBI_TaxID=8620;
RN [1]
RP PROTEIN SEQUENCE, FUNCTION, AND SUBCELLULAR LOCATION.
RC TISSUE=Venom;
RX PubMed=1848702; DOI=10.1073/pnas.88.6.2437;
RA de Weille J.R., Schweitz H., Maes P., Tartar A., Lazdunski M.;
RT "Calciseptine, a peptide isolated from black mamba venom, is a specific
RT blocker of the L-type calcium channel.";
RL Proc. Natl. Acad. Sci. U.S.A. 88:2437-2440(1991).
RN [2]
RP SYNTHESIS.
RX PubMed=1450521;
RA Kuroda H., Chen Y.-N., Watanabe T.X., Kimura T., Sakakibara S.;
RT "Solution synthesis of calciseptine, an L-type specific calcium channel
RT blocker.";
RL Pept. Res. 5:265-268(1992).
RN [3]
RP SYNTHESIS OF 41-48.
RX PubMed=9636051; DOI=10.1021/bi9802723;
RA Kini R.M., Caldwell R.A., Wu Q.Y., Baumgarten C.M., Feher J.J., Evans H.J.;
RT "Flanking proline residues identify the L-type Ca2+ channel binding site of
RT calciseptine and FS2.";
RL Biochemistry 37:9058-9063(1998).
CC -!- FUNCTION: This specific blocker of the L-type calcium channel
CC (Cav1/CACNA1) is a smooth muscle relaxant and an inhibitor of cardiac
CC contractions. {ECO:0000269|PubMed:1848702}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:1848702}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC -!- MISCELLANEOUS: The sensitivity is higher in cells of the cardiovascular
CC system. Neuronal, and insulinoma cells L-type calcium channel are more
CC resistant. A total resistance is found in skeletal muscle cells.
CC -!- SIMILARITY: Belongs to the snake three-finger toxin family. Short-chain
CC subfamily. L-type calcium blocker sub-subfamily. {ECO:0000305}.
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DR PIR; A39165; A39165.
DR AlphaFoldDB; P22947; -.
DR SMR; P22947; -.
DR GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR GO; GO:0005246; F:calcium channel regulator activity; IEA:UniProtKB-KW.
DR GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR Gene3D; 2.10.60.10; -; 1.
DR InterPro; IPR045860; Snake_toxin-like_sf.
DR InterPro; IPR018354; Snake_toxin_con_site.
DR SUPFAM; SSF57302; SSF57302; 1.
DR PROSITE; PS00272; SNAKE_TOXIN; 1.
PE 1: Evidence at protein level;
KW Calcium channel impairing toxin; Cardiotoxin; Direct protein sequencing;
KW Disulfide bond; Ion channel impairing toxin; Secreted; Toxin;
KW Voltage-gated calcium channel impairing toxin.
FT CHAIN 1..60
FT /note="Calciseptin"
FT /evidence="ECO:0000269|PubMed:1848702"
FT /id="PRO_0000093667"
FT REGION 41..48
FT /note="Important for binding to L-type calcium channels"
FT /evidence="ECO:0000269|PubMed:9636051"
FT DISULFID 3..22
FT /evidence="ECO:0000250|UniProtKB:P0C1Z0"
FT DISULFID 17..39
FT /evidence="ECO:0000250|UniProtKB:P0C1Z0"
FT DISULFID 41..52
FT /evidence="ECO:0000250|UniProtKB:P0C1Z0"
FT DISULFID 53..58
FT /evidence="ECO:0000250|UniProtKB:P0C1Z0"
SQ SEQUENCE 60 AA; 7044 MW; 2F14B05972A40FFF CRC64;
RICYIHKASL PRATKTCVEN TCYKMFIRTQ REYISERGCG CPTAMWPYQT ECCKGDRCNK
