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chpB

Gene
chpB
Protein
Chaplin-B
Organism
Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145)
Length
237 amino acids
Function
One of 8 partially redundant surface-active proteins required for efficient formation of aerial mycelium; the short chaplins assemble into a hydrophobic, amyloidal fibrillar surface layer that envelopes and protects aerial hyphae and spores, presumably anchored to the long chaplins (PubMed:12832396, PubMed:12832397, PubMed:15228525, PubMed:17462011). Chaplins have an overlapping function with the surface-active SapB peptide; chaplins are essential on minimal medium while on rich medium both chaplins and SapB are required for efficient aerial hyphae formation (PubMed:17462011). The long chaplins (ChpA, ChpB, ChpC) are not absolutely necessary for short chaplin localization or rodlet formation, but probably play a role in initiating aerial hyphae development (PubMed:22296345). Chaplins are also involved in cell attachment to a hydrophobic surface (PubMed:19682261).
Similarity
Belongs to the chaplin family. Long chaplin subfamily.
Mass
22.741 kDa
Sequence
MRRVTRNGVLAVAASGALAVTMPAYAAFASDGAGAEGSAAGSPGLISGNTVQLPVDVPVDVCGNTVNVVGLLNPAAGNGCADSGEPGASYQAAGASGGTSGSATEATSGGAAAEGSGKDSPGVLSGNGVQLPVHLPVNVSGNSVNVVGIGNPAVGNESTNDSGDHPEPVRPPAEPEPSAPEEERAGPGPSAHAAPPREEVSLAHTGTDRTLPTLAGGAALVLGGTVLYRRFRPGSGD

Gene
chpB
Protein
Endoribonuclease toxin ChpB
Organism
Escherichia coli (strain K12)
Length
116 amino acids
Function
Toxic component of a type II toxin-antitoxin (TA) system. ChpB is a sequence-specific mRNA and (weak) tmRNA endoribonuclease that inhibits protein synthesis and induces bacterial stasis. Cleavage is independent of the ribosome. Cleavage occurs at ACY sequences where Y is not C. The endoribonuclease activity is not as strong as that of MazF. The endoribonuclease activity (a toxin) is inhibited by its labile cognate antitoxin ChpS. Toxicity results when the levels of ChpS decrease in the cell, leading to mRNA degradation. Both ChpS and ChpB probably bind to the promoter region of the chpS-chpB operon to autoregulate their synthesis. mRNA interferases play a role in bacterial persistence to antibiotics (PubMed:21788497).
Similarity
Belongs to the PemK/MazF family.
Mass
12.492 kDa
Sequence
MVKKSEFERGDIVLVGFDPASGHEQQGAGRPALVLSVQAFNQLGMTLVAPITQGGNFARYAGFSVPLHCEEGDVHGVVLVNQVRMMDLHARLAKRIGLAADEVVEEALLRLQAVVE