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Title
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Primary structure of the mating pheromone Er-1 of the ciliate Euplotes raikovi.
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Authors
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S.Raffioni,
P.Luporini,
B.T.Chait,
S.S.Disper,
R.A.Bradshaw.
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Ref.
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J Biol Chem, 1988,
263,
18152-18159.
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PubMed id
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Abstract
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The complete amino acid sequence of the mating pheromone Er-1 purified from
Euplotes raikovi homozygous for mat-1 was determined by automated Edman
degradation of the whole protein and peptides generated by cyanogen bromide,
trypsin, Staphylococcus aureus V8 protease, and chymotrypsin. The proposed
sequence is:
Asp-Ala-Cys-Glu-Gln-Ala-Ala-Ile-Gln-Cys-Val-Glu-Ser-Ala-Cys-Glu-Ser-Leu-
Cys-Thr-Glu-Gly-Glu-Asp-Arg-Thr-Gly-Cys-Tyr-Met-Tyr-Ile-Tyr-Ser-Asn-Cys-
Pro-Pro-Tyr-Val The calculated molecular weight is 4411.0, which is in agreement
with the averaged mass of 4410.2 obtained by fission fragment ionization mass
spectrometry. Previously reported values of the native molecular weight,
determined by gel filtration, have ranged from 9,000 to 12,000. Thus, the native
structure is likely a dimer (or larger aggregate) of identical subunits with the
three disulfide bonds present occurring as intrachain links. Secondary structure
predictions suggest a helical structure at the amino terminus. A comparison of
the Er-1 amino acid sequence with known protein sequences did not reveal any
significant similarities.
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