Background:
Streptomyces clavuligerus is prolific producer of cephamycin C, a medically important antibiotic.
In our former study, cephamycin C titer was 2-fold improved by disrupting homoserine dehydrogenase (hom) gene of aspartate pahway in Streptomyces clavuligerus NRRL3585.
Objective:
In this article, we aimed to provide a comprehensive understanding at the proteome level on potential complex
metabolic changes as a consequence of hom disruption in Streptomyces clavuligerus AK39.
Methods:
A comparative proteomics study was carried out between the wild type and its hom disrupted AK39 strain by 2
Dimensional Electrophoresis-Matrix Assisted Laser Desorption and Ionization Time-Of-Flight Mass Spectrometry (2DE
MALDI-TOF/MS) and Nanoscale Liquid Chromatography-Tandem Mass Spectrometry (nanoLC-MS/MS) analyses. Clusters of Orthologous Groups (COG) database was used to determine the functional categories of the proteins. The theoretical
pI and Mw values of the proteins were calculated using Expasy pI/Mw tool.
Results:
“Hypothetical/Unknown” and “Secondary Metabolism” were the most prominent categories of the differentially
expressed proteins. Upto 8.7-fold increased level of the positive regulator CcaR was a key finding since CcaR was shown to
bind to cefF promoter thereby direcly controlling its expression. Consistently, CeaS2, the first enzyme of CA biosynthetic
pathway, was 3.3-fold elevated. There were also many underrepresented proteins associated with the biosynthesis of several
Non-Ribosomal Peptide Synthases (NRPSs), clavams, hybrid NRPS/Polyketide synthases (PKSs) and tunicamycin. The
most conspicuously underrepresented protein of amino acid metabolism was 4-Hydroxyphenylpyruvate dioxygenase
(HppD) acting in tyrosine catabolism. The levels of a Two Component System (TCS) response regulator containing a CheYlike receiver domain and an HTH DNA-binding domain as well as DNA-binding protein HU were elevated while a TetRfamily transcriptional regulator was underexpressed.
Conclusion:
The results obtained herein will aid in finding out new targets for further improvement of cephamycin C production in Streptomyces clavuligerus.
Regulation of cephamycin C synthesis, aspartokinase, dihydrodipicolinic acid synthetase, and homoserine dehydrogenase by aspartic acid family amino acids in Streptomyces clavuligerus.