ISSN:
1365-2958
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Biologie
,
Medizin
Notizen:
SpoIVB is essential for intercompartmental signalling in the σK-checkpoint of Bacillus subtilis. SpoIVB is synthesized in the spore chamber and is the signal which activates proteolytic processing of pro-σK to its mature and active form σK. We show here that SpoIVB is a serine peptidase of the SA clan. Expression of SpoIVB in Escherichia coli has shown that SpoIVB is able to self-cleave into at least three discrete products, and in vitro studies have shown cleavage in trans. Autoproteolysis of SpoIVB is tightly linked to the initiation of the two developmental functions of this protein, signalling of pro-σK processing and a yet, uncharacterized, second function which is essential for the formation of heat-resistant spores. In B. subtilis, SpoIVB is synthesized as a zymogen and is subject to two levels of proteolysis. First, autoproteolysis generating intermediate products, at least one of which is proposed to be the active form, followed by processing by one or more enzymes to smaller species. This could provide a mechanism for switching off the active SpoIVB intermediate(s) and suggests a similarity to other proteolytic cascades such as those found in blood coagulation.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1046/j.1365-2958.2000.01946.x
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