{"product_id":"recombinant-escherichia-coli-small-ribosomal-subunit-protein-bs1-rpsa-bhp10515053","title":"Recombinant Escherichia coli Small ribosomal subunit protein bS1 (rpsA)","description":"\u003ch2\u003eOverview\u003c\/h2\u003e\u003cp\u003eRecombinant Escherichia coli Small ribosomal subunit protein bS1 (rpsA) is a recombinant protein preparation derived from Escherichia coli (strain K12). It is commonly used as a defined reagent for assay development, binding studies, and analytical controls where consistent protein specifications are required.\u003c\/p\u003e\u003ch2\u003eKey elements and design rationale\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eExpressed region:\u003c\/strong\u003e 1-557aa.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExpression system:\u003c\/strong\u003e E.coli (may influence folding and post-translational modifications).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTag\/format:\u003c\/strong\u003e C-terminal 6xHis-tagged; Liquid or Lyophilized powder.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExpected size:\u003c\/strong\u003e 68.1 kDa (as provided).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePurity:\u003c\/strong\u003e Greater than 85% as determined by SDS-PAGE.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eRegion choice, expression system, and tag\/format can influence folding, post-translational modifications, and interaction behavior in downstream assays.\u003c\/p\u003e\u003ch2\u003eBiological background\u003c\/h2\u003e\u003cp\u003eRequired for translation of most natural mRNAs except for leaderless mRNA. Binds mRNA upstream of the Shine-Dalgarno (SD) sequence and helps it bind to the 30S ribosomal subunit; acts as an RNA chaperone to unfold structured mRNA on the ribosome but is not essential for mRNAs with strong SDs and little 5'-UTR structure, thus it may help fine-tune which mRNAs that are translated. Unwinds dsRNA by binding to transiently formed ssRNA regions; binds about 10 nucleotides. Has a preference for polypyrimidine tracts. Negatively autoregulates its own translation. ; It is not clear if it plays a role in trans-translation (a process which rescues stalled ribosomes). Evidence for its role; binds to tmRNA with very high affinity, is required for binding of tmRNA to 30S subunit. Thought to play a role only in translation of the tmRNA in vitro. Evidence against its role; overexpression of whole protein or various S1 fragments inhibits translation, they have no effect on trans-translation, and an in vitro system with S1-less ribosomes performs trans-translation. In trans-translation Ala-aminoacylated transfer-messenger RNA (tmRNA, product of the ssrA gene; the 2 termini fold to resemble tRNA(Ala) while it encodes a short internal open reading frame (the tag peptide)) acts like a tRNA, entering the A-site of the ribosome and displacing the stalled mRNA (which is subsequently degraded). The ribosome then switches to translate the ORF on the tmRNA, the nascent peptide is terminated with the 'tag peptide' encoded by the tmRNA and thus targeted for degradation. ; In case of infection by bacteriophage Qbeta, part of the viral RNA-dependent RNA polymerase complex; this subunit is required for RNA replication initiation activity during synthesis of (-) strand RNA from the (+) strand genomic RNA but not for (+) strand synthesis from the (-) strand. Binds an approximately 70 nucleotide RNA internal to the viral replicase gene (the M-site). Others have reported it is not involved in RNA replication initiation but rather in termination of RNA synthesis and is required for termination whether it is the (+) or (-) strand that is being synthesized. ; In case of infection by bacteriophage T4, plays a significant role in substrate choice by viral endoribonuclease RegB.\u003c\/p\u003e\u003ch2\u003eResearch relevance and current trends\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eDomain- and isoform-aware assay design to improve biological interpretation across model systems.\u003c\/li\u003e\n\u003cli\u003eQuantitative workflows emphasizing calibration standards, spike-in controls, and cross-lot comparability.\u003c\/li\u003e\n\u003cli\u003eIn vitro binding\/kinetics profiling (SPR\/BLI) to connect biochemical interactions with cellular phenotypes.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eCommon research applications\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003ePrepare aliquots of rpsA for reproducible in vitro assays (minimize freeze–thaw).\u003c\/li\u003e\n\u003cli\u003eUse rpsA as a calibration standard in quantitative assays (standard curve setup).\u003c\/li\u003e\n\u003cli\u003eMeasure binding interactions to rpsA by SPR\/BLI (kinetic profiling in vitro).\u003c\/li\u003e\n\u003cli\u003eGenerate antibodies to rpsA and benchmark specificity in ELISA\/WB (control samples).\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eInterpret results in the context of the biological system, assay format, and any known domain\/isoform constraints for the target.\u003c\/p\u003e\u003ch2\u003eNotes for experimental interpretation\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eConsider species- and isoform-specific differences when comparing results across models or homologs.\u003c\/li\u003e\n\u003cli\u003eFor quantitative assays, include appropriate negative controls and matrix-matched spike-in concepts to assess non-specific signal.\u003c\/li\u003e\n\u003c\/ul\u003e\u003c!-- Sources (internal): - UniProtKB entry (P0AG67) — UniProt: https:\/\/www.uniprot.org\/uniprotkb\/P0AG67 - NCBI Gene search (rpsA) — NCBI: https:\/\/www.ncbi.nlm.nih.gov\/gene\/?term=rpsA - PubMed search — NLM: https:\/\/pubmed.ncbi.nlm.nih.gov\/?term=rpsA - Reactome pathway browser — Reactome: https:\/\/reactome.org\/ - InterPro protein family resource — EMBL-EBI: https:\/\/www.ebi.ac.uk\/interpro\/ --\u003e","brand":"CUSABIO TECHNOLOGY LLC","offers":[{"title":"1 mg","offer_id":53059277685101,"sku":"CSB-EP314176ENV-1MG","price":2466.0,"currency_code":"USD","in_stock":true},{"title":"100 ug","offer_id":53059401810285,"sku":"CSB-EP314176ENV-100UG","price":578.0,"currency_code":"USD","in_stock":true},{"title":"20 ug","offer_id":53059401843053,"sku":"CSB-EP314176ENV-20UG","price":306.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0949\/7424\/7277\/files\/CSB-EP314176ENV-SDS.jpg?v=1772280217","url":"https:\/\/www.ebiohippo.com\/products\/recombinant-escherichia-coli-small-ribosomal-subunit-protein-bs1-rpsa-bhp10515053","provider":"BioHippo","version":"1.0","type":"link"}