Previous studies on inhibition of the Escherichia coli glycerol kinase enzyme
have suggested that subunit-subunit or domain bridging interactions form part of the
network in communicating ligand binding to inhibition. In this study, five amino acids
were identified to be in close proximity to an Arg369 residue which is a domain bridging
residue. Three of the amino acid residues (Q37, Y39 and Q104) are in domain I of the
enzyme subunit, while the other two (M308 and Q314) are in domain II of the enzyme
subunit.
To evaluate the importance of each domain bridging residue in IIAGlc inhibition,
alanine substitutions were made of the residues, and the kinetic properties characterized
with respect to IIAGlc inhibition. Kinetic parameters obtained for each variant glycerol
kinase enzyme was compared to values obtained for the Wild Type enzyme to assess the
importance of the amino acid residue in IIAGlc inhibition. The effects of the substitutions
on FBP inhibition as well as catalysis of the enzyme were also analyzed by obtaining
kinetic parameters for each of the variant enzymes.
The results from this study indicate that the domain I bridging interactions with
Arg369 are important in IIAGlc regulation of the E. coli glycerol kinase enzyme. The
domain II bridging interactions appear to be unimportant in regulating IIAGlc inhibition.
Two of the domain I bridging residues studied were also found to be important in FBP
inhibition. These results indicate that some the domain bridging residues seen to be
involved in IIAGlc regulation also appear to be involved in FBP regulation. In catalysis,
with the exception of Q314, the rest of the domain I and II bridging residues appear to be
important for substrate binding and/or catalysis.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2010-08-8303 |
| Date | 2010 August 1900 |
| Creators | Acquaye, Edith Abena |
| Contributors | Pettigrew, Donald W. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | thesis, text |
| Format | application/pdf |
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