The metal-binding properties of the long chaplin from Streptomyces mobaraensis: A bioinformatic and biochemical approach

• Published in: Journal of inorganic biochemistry 2020-01, Vol.202, p.110878-110878, Article 110878
• Main Authors: Anderl, Anita, Kolmar, Harald, Fuchsbauer, Hans-Lothar
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Chaplin; Computational Biology; d-Block metal; His-rich protein; Histidine - metabolism; Metal binding; Metals, Heavy - metabolism; Sequence Homology; Streptomyces - growth & development; Streptomyces - metabolism; Streptomyces mobaraensis; Transporter
• ISSN: 0162-0134; 1873-3344
• DOI: 10.1016/j.jinorgbio.2019.110878

Chaplins are amphiphilic proteins coating the surface of aerial hyphae under formation of amyloid-like rodlet layers in streptomycetes. The long chaplin from Streptomyces mobaraensis, Sm-Chp1, harbors extended histidine-rich stretches allowing protein attachment to metal affinity resins. A comprehensive BLASTP search revealed similarity with many putative metal-binding proteins but the deduced sequence motifs were not shared by histidine-rich domains of well-studied proteins. Biochemical analyses showed affinity of Sm-Chp1 for Ni2+, Cu2+ and Zn2+, a binding capacity of 7–8 metal ions, and dissociation constants in a double digit micromolar range. The occurrence of genes for membrane-bound metal transporters and several intra- and extracellular metalloenzymes in the genome of S. mobaraensis suggests that Sm-Chp1 may be a novel type of translocase shifting metals across the rodlet layer from the environment into the cell wall. Chaplin 1 from Streptomyces mobaraensis, probably covering the surface of aerial hyphae, harbors histidine-rich stretches. The study revealed affinity for d-block metals and existence of 7–8 metal binding sites. Bioinformatic analyses suggest that chaplin 1 may be a novel translocase shifting metals from the environment to the cell wall. [Display omitted] •The long chaplin from Streptomyces mobaraensis interacts with d-block metals.•The amphiphilic protein harbors extended histidine-rich domains.•Binding sites for seven and eight metal ions are available.•Distinct histidine sequence motifs are specific features of chaplin 1.•Chaplin 1 is likely a novel metal translocase at the surface of aerial hyphae.