Characterization of the interaction of putrescine and the adenosine-3' ,5'-cyclic monophosphate-cAMP receptor protein complex in the regulation of the speC gene encoding ornithine decarboxylase in Escherichia coli

Ornithine decarboxylase (ODC) catalyzes the decarboxylation of ornithine to produce the diamine, putrescine, in the bacterium Escherichia coli. The speC gene encoding ODC has been shown to be subject to transcriptional repression by either putrescine or the cAMP- cAMP receptor protein (CRP) complex. To determine whether these regulatory modes are independent, the expression of ODC was determined by measuring the specific activity of ODC in crude extracts prepared from exponentially grown cultures of wild type ~ coli K-12 as well as in strains unable to synthesize cAMP (cya) and/or CRP (crp). 1-5 mM cAMP repressed ODe activity 22-38% in wild type, 57-66% in the cya strain, and only 7-18% in the ~ strains. 2-10 mM putrescine repressed ODe activity 30-32% in wild type, 48-49% in the cya strain, and 37-38% in the ~ strain. As putrescine repressed ODe activity in the absence of eRP protein (i.e. in a crp strain), putrescine-mediated repression of ODe appears to be independent of the repression of ODC by the cAMP-eRP complex. This conclusion was verified by demonstrating th t .oDC repression by putrescine and cAMP together was additive.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Veterinary Medical Sciences

Department dc:contributor.department

Veterinary Medical Sciences

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1988

Author dc:creator

• Busse, Leigh Anne

Chair dc:contributor.committeechair

• Boyle, Stephen M.

Committee members dc:contributor.committeemember

• Falkinham, Joseph O. III
• Sriranganathan, Nammalwar

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-04122010-083645

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/42041