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Updated: Jan 24, 2026
Visual and Microscopic Evaluation of Streptomyces Developmental Mutants
Published on: September 12, 2018
Identification of LcpRBA3(2), a novel regulator of lcp expression in Streptomyces coelicolor A3(2)
Anna Coenen1, Sylvia Oetermann1, Alexander Steinbüchel2,3
1Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Münster, Germany.
Abstract:
Streptomyces coelicolor A3(2) is a rubber-degrading actinomycete that harbors one gene coding for a latex clearing protein (lcpA3(2)). Within the genome of S. coelicolor A3(2), we identified a gene coding for a novel protein of the TetR family (LcpRBA3(2)) downstream of lcpA3(2) and demonstrated its binding upstream of lcpA3(2). This indicates a role of LcpRBA3(2) in the regulation of lcp expression. LcpRBA3(2) shows no homology to LcpRVH2, a putative regulator of lcp expression in Gordonia polyisoprenivorans VH2. Additionally, LcpRVH2 homologs did not occur in the genome of S. coelicolor A3(2). Reverse transcriptase (RT) experiments showed that the expression of lcpA3(2) and lcpRBA3(2) is induced with poly(cis-1,4-isoprene) as sole carbon source. For further experiments, we heterologously expressed lcpRBA3(2) in Escherichia coli, purified the protein, and subsequently verified a binding of LcpRBA3(2) upstream of lcpA3(2). The operator site was examined by a DNase I footprinting assay: it comprises 31 bp and exhibits an inverted repeat of nine bases for the putative binding region. Interestingly, two N-terminal DNA-binding HTH domains of the TetR-type (PF00440) were identified within the sequence of LcpRBA3(2). The native molecular weight of LcpRBA3(2) was determined as 44 kDa by size exclusion chromatography which correlates to the molecular weight of a monomer. Normally, proteins of the TetR family occur as dimers so that the monomeric state is a novelty. Furthermore, LcpRBA3(2) homologs were identified in silico in several Lcp-containing actinomycetes, suspecting a conserved regulation mechanism. Apparently, the expression of lcps is regulated either by an LcpRB or by an LcpR.
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