MATERIALS AND METHODS FOR ENHANCED HEAT STABILITY AND KINETIC PARAMETERS OF ADP-GLUCOSE PYROPHOSPHORYLASE

摘要

Materials and methods for enhancing heat stability of AGPase by mutating amino acids within the large subunit of AGPase are disclosed. Polynucleotides that encode a mutant large subunit of AGPase provide for increased heat stability when expressed with AGPase small subunit. In one embodiment, the mutant large subunit has a single amino acid mutation. Exemplified mutant large subunits include those of SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO:16, SEQ ID NO: 17, SEQ ID NO: 18, SEQ ID NO: 19, SEQ ID NO:20, SEQ ID NO:21, SEQ ID NO:22, SEQ ID NO:23, SEQ ID NO:25, SEQ ID NO:27, and SEQ ID NO:52. In further embodiments, the mutant large subunit comprises two or more amino acid mutations. An exemplified mutant large subunit comprising two or more amino acid mutations is designated as SH2N131R:C424V having an amino acid sequence shown in SEQ ID NO:23. In another exemplified embodiment, a mutant large subunit of the invention, designated herein as SH2-E, comprises 8 amino acid mutations.