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- ******************************************
- * Avidin / Streptavidin family signature *
- ******************************************
-
- Avidin [1] is a minor constituent of egg white in several groups of oviparous
- vertebrates. Avidin, which was discovered in the 1920's, takes its name from
- the avidity with which it binds biotin. These two molecules bind so strongly
- that is highly difficult to separate them. Streptavidin is a protein produced
- by Streptomyces avidinii which also binds biotin and whose sequence is
- evolutionary related to that of avidin.
-
- Avidin and streptavidin both form homotetrameric complexes of noncovalently
- associated chains. Each chain forms a very strong and specific non-covalent
- complex with one molecule of biotin.
-
- The C-terminal domain of a protein from purple sea urchin has been shown [2]
- to be related to the sequences of avidin and streptavidin. This protein seems
- to consist of an N-terminal section that contains at least nine EGF-type A
- repeats followed by a C-terminal avidin-like domain.
-
- As a signature sequence for this family of proteins we selected a conserved
- domain located in the C-terminal section of avidin/streptavidin and the
- avidin-like domain.
-
- -Consensus pattern: [DN]-x(2)-K-[STA]-x(2)-V-G-x-[DN]-x-[FW]-T-[KR]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
- -Last update: October 1993 / Text revised.
-
- [ 1] Green N.M.
- Meth. Enzymol. 184:51-67(1990).
- [ 2] Hunt L.T., Barker W.C.
- FASEB J. 3:1760-1764(1989).
-