Gene encoding the group B streptococcal protein R4, its presence in clinical reference laboratory isolates & R4 protein pepsin sensitivity.

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dc.contributor.authorSmith, B Len_US
dc.contributor.authorFlores, Aen_US
dc.contributor.authorDechaine, Jen_US
dc.contributor.authorKrepela, Jen_US
dc.contributor.authorBergdall, Aen_US
dc.contributor.authorFerrieri, Pen_US
dc.date.accessioned2004-05-03en_US
dc.date.accessioned2009-05-27T08:42:03Z
dc.date.available2004-05-03en_US
dc.date.available2009-05-27T08:42:03Z
dc.date.issued2004-05-03en_US
dc.description.abstractBACKGROUND & OBJECTIVES: R proteins were first identified by Lancefield in group B Streptococcus (GBS) as resistant to trypsin at pH8 and sensitive to pepsin at pH2. The R4 protein found predominantly in type III and some type II and V invasive isolates conforms to these criteria. The Rib protein, although structurally and epidemiologically similar to R4, was reported as resistant to both proteases. We report here the gene encoding the R4 protein from a type III group B streptococcal isolate (76-043) well characterized in our laboratory. METHODS: Trypsin extracted GBS proteins were assayed for protease sensitivities by double-diffusion Ouchterlony using varying conditions for the enzyme pepsin. Standard haemoglobin assay was used to examine pepsin enzymatic activity. Thirty clinical isolates of varying protein profiles identified by double-diffusion from our reference strain laboratory were screened by PCR and Southern technique. SDS-PAGE gel purified R4 amino acid sequences were determined and used to design oligonucleotide primers for screening a 76-043 genomic library. RESULTS: R4 was sensitive to pepsin at pH2 but appeared resistant at pH4, the reported pH used for Rib. By standard haemoglobin assay and trypsin extract studies of R4 protein, pepsin was shown to be active at pH2, yet easily inactivated; assays of GBS surface proteins are critical at pH2. Of the amino acids initially sequenced from R4, 88 per cent (61/69) showed identity to Rib; the r4 nucleotide sequence was identical to that of rib. All isolates with strong positive protein reactions for R4 were positive in both PCR and Southern technique, whereas isolates expressing alpha, beta, R1/R4, and R5 (BPS) protein profiles were not. INTERPRETATION & CONCLUSION: Sequenced PCR products aligned with identity to the R4 and Rib nucleotide sequences and confirmed the identity of these proteins and their molecular sequences.en_US
dc.description.affiliationDepartments of Laboratory Medicine & Pathology & Pediatrics, University of Minnesota Medical School & Department of Biology, Luther College, USA.en_US
dc.identifier.citationSmith BL, Flores A, Dechaine J, Krepela J, Bergdall A, Ferrieri P. Gene encoding the group B streptococcal protein R4, its presence in clinical reference laboratory isolates & R4 protein pepsin sensitivity. Indian Journal of Medical Research. 2004 May; 119 Suppl(): 213-20en_US
dc.identifier.urihttps://imsear.searo.who.int/handle/123456789/25347
dc.language.isoengen_US
dc.source.urihttps://icmr.nic.in/ijmr/ijmr.htmen_US
dc.subject.meshAmino Acid Sequenceen_US
dc.subject.meshBacterial Proteins --chemistryen_US
dc.subject.meshBase Sequenceen_US
dc.subject.meshDNA, Bacterialen_US
dc.subject.meshMolecular Sequence Dataen_US
dc.subject.meshPepsin A --metabolismen_US
dc.subject.meshReference Standardsen_US
dc.subject.meshStreptococcus agalactiae --metabolismen_US
dc.titleGene encoding the group B streptococcal protein R4, its presence in clinical reference laboratory isolates & R4 protein pepsin sensitivity.en_US
dc.typeJournal Articleen_US
dc.typeResearch Support, Non-U.S. Gov'ten_US
dc.typeResearch Support, U.S. Gov't, P.H.S.en_US
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