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Histidine ammonia-lyase from Streptomyces griseus
P C Wu1, T A Kroening, P J White
1Department of Microbiology, Ohio State University, Columbus 43210.
Gene
|June 15, 1992
Summary
Histidine ammonia-lyase (HutH) from Streptomyces griseus was purified and its gene cloned. This enzyme exhibits unique properties, suggesting it may represent a distinct histidase family.
Area of Science:
- Biochemistry
- Molecular Biology
- Microbial Genetics
Background:
- Histidine ammonia-lyase (histidase; HutH) is crucial for histidine metabolism.
- Understanding bacterial histidases provides insights into metabolic pathways and enzyme evolution.
Purpose of the Study:
- To purify and characterize histidase from Streptomyces griseus.
- To clone and analyze the hutH gene encoding histidase.
- To investigate the evolutionary relationship of streptomycete histidase.
Main Methods:
- Enzyme purification to homogeneity.
- N-terminal amino acid sequencing.
- Gene cloning and nucleotide sequencing.
- Enzyme kinetics and inhibition studies.
- Promoter analysis using promoter-probe assays.
Main Results:
- Purified HutH showed typical saturation kinetics and competitive inhibition by D-histidine and histidinol phosphate.
- The hutH gene encodes a 53 kDa protein with an N-terminus matching the purified enzyme.
- A potential Streptomyces promoter was identified upstream of hutH, but lacked a clear ribosome-binding site.
- Sequence analysis revealed no similarity to other known histidase proteins, suggesting a distinct family.
Conclusions:
- Streptomyces histidase (HutH) possesses unique kinetic properties and gene organization.
- The findings suggest that streptomycete histidase may constitute a distinct family compared to bacterial and mammalian counterparts.
- Further research is warranted to fully elucidate the structure-function relationship and evolutionary significance of HutH.