Switch of Regulatory Domains of P-protein and T-protein from E. coli / 中国生物化学与分子生物学报

Chorismic acid is a mid-metabolite that plays a central role in the metablism process distributing in the bacterium, epiphyte and plants. It is a common precursor substance of the all aromatic amino acids that can turn into phenylalanine and tyrosine catalyzed by bi-functional enzyme chorismate mutase (CM)-prephenate dehydratase (PDT) and chorismate mutase-prephenate dehydrogenase (PDH) respectively. CMp-PDT with its regulate domain Rp were called P-protein and CMt-PDH with its regulate domain Rt were called T-protein. P-protein and T-protein from E. coli. have a similar structure, both of which contained three domains: CMp, PDT, Rp in P-protein and CMt, PDH, Rt in T-protein. P-protein and T-protein are regulated by their effectors phenylalanine and tyrosine respectively through binding to their Rp and Rt domains. Rp and Rt domains were switched between P-protein and T-protein by cloning of chimeric proteins. The results showed that regulatory effects were switched along the switch of R domains and the switch of the regulatory domains lead to the switch of effectors. It means that the combination of the regulatory domain and the effector is specific and the regulating of the regulatory domain to the enzyme activity is non-specific. This property of R domains may make them possible molecular elements in the study of molecular machines.

Serological Analysis and Epidemiologic Characteristics of Group A Streptococci in Seoul(1998-2000)

PURPOSE: Group A streptococci have a cell wall which consists of M protein and T protein. T protein is known to be helpful in the understanding of the epidemiology of group A streptococci. To study the epidemiologic characteristics, we serotyped T protein of group A streptococci obtained from patients admitted to hospitals, or who visited OPD in five districts of Seoul the during last three years. METHODS: Group A streptococci were obtained in five districts in north, northeast, central, northwest and south Seoul from 1998 through 2000. All isolated group A streptococci were serotyped with T protein antisera(Institute of Sera and Vaccine, Prague, Czech Republic). RESULTS: In 1998, analysis of obtained total number of 92 strains revealed that T12, T4, and NT acounted for 72.2%. Among seven cases of scarlet fever, T12 was isolated in four cases and T4 was found in three cases. Two cases of tonsilar abscess produced T8 and NT. One case of cervical lymphadenitis showed T12. In 1999, 41 cases were studied showing that T12, T4, and T1 contributed 68%. Among five cases of scarlet fever, T12 and T4 make up three case. There were two cases of pneumonia(T4 and T1) and one case of cervical lymphadenitis(T8/25). In 2000, the study was performed in four districts except the central area. Among 83 isolates, T12, T4 and T1 accounted for 63.9%. There were three cases of scarlet fever(T12, T4, T5), one case of tonsillar abscess(T12), one case of pneumonia(NT) and one case of sepsis(T1). CONCLUSION: Serological analysis of T protein of group A streptococci shows no endemic specificity. The yearly pattern reveals that T12 had been decreasing but T1 had shown the opposite trend.

Genotypic and Phenotypic Analysis Among Clinical Isolate of Streptococcus pyogenes in Seoul , Korea

A total of 152 strains of Streptococcus pyogenes were isolated from patients with pharyngitis, scarlet fever, skin infection, or invasive streptococcal infections in Seoul, Korea from January 1988 to December 1999. All isolates were epidemiologically characterized to decide phenotypes by T protein serotype and serum opacity factor (OF) detection. Genetic diversity of the isolates were analyzed by emm genotyping and pulsed-field gel electrophoresis (PFGE). T protein serotype showed 17 kinds in distribution and T12 (40.1% of study strains), T4 (19.1%), and T1 (7.9%) were the prevalent ones. When sources of S. pyogenes isolates were analyzed by T serotype distribution, T12 type was predominant in pharyngitis and skin infection isolates which contributed to 30 strains (49.2%) and 11 strains (18.0%), respectively. When T serotype of S. pyogenes isolates were analyzed by emm genotype distribution, of the 61 isolates of T12 type, 48 strains (78.7%) belonged to the emm type 12 (M12) and of the 29 isolates of T4 type, 27 strains (93.1%) belonged to the emm genotype 4 (M4). PFGE of genomic DNA of different emm genotype (emm12, emm4 and emm1) showed distinctive patterns. When the DNA of same emm gene type isolates were analyzed genetic relatedness by PFGE pattern, emm4, emm1, and emm12 types showed over 90%, 75%, and 70% of genetic similarity, respectively. Therefore, it was suggested that these emm genotype isolates were closely related genetically whereas among the isolates of other emm genotypes showed less than 30% of genetic similarity. Show genotypes are more diverse in comparison with phenotypes. In even epidemiologically unrealated isolates, genetic subtypes appeared correlated. The phenotypic and genotypic analysis used in the study were discriminative and appropriate for epidemiological study of S. pyogenes.

Serotyping of Group A Streptococci Isolated from Healthy School Children and Patients with Pharyngotonsillitis / 감염

BACKGROUND: To evaluate serological typing of T(epidemiologic marker) and M protein(major virulence antigen) is important to understand pathogenesis and epidemiology of streptococcal infection. The purpose of this study is to find out whether there were major difference in distribution of serotypes isolated from healthy school children and patients with pharyngotonsillitis, and to characterize the geographical differences in distribution of the serotypes. METHOD: Twenty-three strains of group A streptococci were isolated from healthy school children in two different areas(Dongdaemun-Ku and Kangsuh-Ku) in Seoul in April and July 1996. 23 strains came from patients living in Dongjak-Ku with pharyngotonsillitis in April 1996. All isolated were serotyped by T agglutination, M precipitation and opacity factor at the WHO Collaborative Center for Reference and Research on Streptococci, University of Minnesota, Minneapolis. RESULTS: 89.1% of the strains were typable by T agglutination, 56.5% by M precipitation, and 52.2% were positive in opacity factor. T types 1, 25, 4, and 12 accounted for 65.2% of patients with pharyngotonsillitis, T types 12, and 25 accounted for 71.5% of healthy children in Dongdaemun-Ku, and T types 28, 6, and 3 accounted for 62.6% of healthy children in Kangsuh-Ku. T types 1, 25, 28, 12, 4 and M types 1, 75, 28, 4, 12 were typed in decreasing order. CONCLUSION: We characterized the differences in serotypes of group A streptocpcci between healthy children and patients. The periodic and seasonal serotyping analysis is important in monitoring and understanding of the epidemiologic patterns of group A streptococci.