The mechanisms of substrate recognition by regulatory proteases are not well
understood. Presently, two opposing models have arisen to describe E. coil Lon's ability
to discriminate between substrates: one suggests the N-terminus involvement while the
second suggests the C-terminus involvement. In this project, the role of the C-terminal
domain as it relates to the recognition of Lon's normal physiological substrates RcsA, an
activator of colanic acid capsular polysaccharide, and SulA, an inhibitor of cell division,
was addressed. Using site-directed mutagenesis, five mutations in Lon (R537G, E538A,
GS40W, R542G, R542P) were isolated. Their phenotypic impact was either similar in
character to wildtype Lon (R537G, E538A) or ��lon cells (G540W, R542G, R542P). The
stabilization of both RcsA and SulA based on phenotypic assays and immunological
detection of lon* strains (G540W, R542G, R542P) suggests the C-terminal domain may
be involved in substrate degradation as opposed to discriminator activity. / Graduation date: 2002
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/32187 |
| Date | 27 August 2001 |
| Creators | Miller, Darcey L. |
| Contributors | Trempy, Janine E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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