scholarly journals Diversity of penA Alterations and Subtypes in Neisseria gonorrhoeae Strains from Sydney, Australia, That Are Less Susceptible to Ceftriaxone

2007 ◽  
Vol 51 (9) ◽  
pp. 3111-3116 ◽  
Author(s):  
David M. Whiley ◽  
E. Athena Limnios ◽  
Sanghamitra Ray ◽  
Theo P. Sloots ◽  
John W. Tapsall
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Neisseria Gonorrhoeae ◽  
Binding Protein ◽  
Amino Acid Sequences ◽  
Penicillin Binding Protein ◽  
Geographic Origins ◽  
Sequence Patterns ◽  
Sydney Australia

ABSTRACT Increasing numbers of Neisseria gonorrhoeae strains with decreased susceptibilities to ceftriaxone and other oral cephalosporins widely used for the treatment of gonorrhea have been isolated in Sydney, Australia, over several years. In this study, we examined the complete penicillin-binding protein 2 (PBP 2) amino acid sequences of 109 gonococci, selected on the basis of their diverse temporal and geographic origins and because they exhibited a range of ceftriaxone MICs: ≤0.03 μg/ml (n = 59), 0.06 μg/ml (n = 43), and 0.125 μg/ml (n = 7). Auxotyping, serotyping, and genotyping by N. gonorrhoeae multiantigen sequence typing sequence-based analysis was also performed. In total, 20 different amino acid sequence patterns were identified, indicating considerable variation in the PBP 2 sequences in this study sample. Only some of the N. gonorrhoeae isolates with significantly higher ceftriaxone MICs contained a mosaic PBP 2 pattern, while more isolates exhibited a nonmosaic PBP 2 pattern containing an A501V substitution. Although particular N. gonorrhoeae genotypes in our sample were shown to be less susceptible to ceftriaxone, the reduced susceptibility to ceftriaxone was not specific to any particular genotype and was observed in a broad range of auxotypes, serotypes, and genotypes. Overall, the results of our study show that N. gonorrhoeae strains exhibiting reduced sensitivity to ceftriaxone are not of a particular subtype and that a number of different mutations in PBP 2 may contribute to this phenomenon.

scholarly journals Amino Acid Substitutions in Mosaic Penicillin-Binding Protein 2 Associated with Reduced Susceptibility to Cefixime in Clinical Isolates of Neisseria gonorrhoeae

2006 ◽  
Vol 50 (11) ◽  
pp. 3638-3645 ◽  
Author(s):  
Sho Takahata ◽  
Nami Senju ◽  
Yumi Osaki ◽  
Takuji Yoshida ◽  
Takashi Ida
Keyword(s):  
Amino Acid ◽  
Neisseria Gonorrhoeae ◽  
Molecular Mechanisms ◽  
Binding Protein ◽  
Complete Sequence ◽  
Clinical Isolates ◽  
Amino Acid Substitutions ◽  
Penicillin Binding Protein ◽  
Fourfold Increase ◽  
Genes Encoding

ABSTRACT The molecular mechanisms of reduced susceptibility to cefixime in clinical isolates of Neisseria gonorrhoeae, particularly amino acid substitutions in mosaic penicillin-binding protein 2 (PBP2), were examined. The complete sequence of ponA, penA, and por genes, encoding, respectively, PBP1, PBP2, and porin, were determined for 58 strains isolated in 2002 from Japan. Replacement of leucine 421 by proline in PBP1 and the mosaic-like structure of PBP2 were detected in 48 strains (82.8%) and 28 strains (48.3%), respectively. The presence of mosaic PBP2 was the main cause of the elevated cefixime MIC (4- to 64-fold). In order to identify the mutations responsible for the reduced susceptibility to cefixime in isolates with mosaic PBP2, penA genes with various mutations were transferred to a susceptible strain by genetic transformation. The susceptibility of partial recombinants and site-directed mutants revealed that the replacement of glycine 545 by serine (G545S) was the primary mutation, which led to a two- to fourfold increase in resistance to cephems. Replacement of isoleucine 312 by methionine (I312M) and valine 316 by threonine (V316T), in the presence of the G545S mutation, reduced susceptibility to cefixime, ceftibuten, and cefpodoxime by an additional fourfold. Therefore, three mutations (G545S, I312M, and V316T) in mosaic PBP2 were identified as the amino acid substitutions responsible for reduced susceptibility to cefixime in N. gonorrhoeae.

scholarly journals Penicillin-Binding Protein 1 ofStaphylococcus aureus Is Essential for Growth

1998 ◽  
Vol 180 (10) ◽  
pp. 2759-2765 ◽  
Author(s):  
Akihito Wada ◽  
Haruo Watanabe
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Binding Protein ◽  
Ofstaphylococcus Aureus ◽  
Penicillin Binding Protein ◽  
Gene Encoding ◽  
Chromosomal Copy

ABSTRACT pbpA, a gene encoding penicillin-binding protein (PBP) 1 of Staphylococcus aureus, was cloned in anEscherichia coli MC1061 transformant which grew on a plate containing 512 μg of vancomycin per ml. This gene encodes a 744-amino-acid sequence which conserves three motifs of PBPs, SXXK, SXN, and KTG. The chromosomal copy of pbpA could be disrupted only when RN4220, a methicillin-sensitive S. aureus strain, had additional copies of pbpA in its episome. Furthermore, these episomal copies of pbpA could not be eliminated by an incompatible plasmid when the chromosomal copy of pbpA was disrupted beforehand. Based on these observations, we concluded that pbpA is essential for the growth of methicillin-sensitive S. aureus.

scholarly journals Characterization and amino acid sequence of a fatty acid-binding protein from human heart

1988 ◽  
Vol 252 (1) ◽  
pp. 191-198 ◽  
Author(s):  
G D Offner ◽  
P Brecher ◽  
W B Sawlivich ◽  
C E Costello ◽  
R F Troxler
Keyword(s):  
Fatty Acid ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Human Heart ◽  
Fatty Acid Binding Protein ◽  
Binding Protein ◽  
Amino Acid Sequences ◽  
British Library ◽  
Fatty Acid Binding ◽  
Acid Binding Protein

The complete amino acid sequence of a fatty acid-binding protein from human heart was determined by automated Edman degradation of CNBr, BNPS-skatole [3′-bromo-3-methyl-2-(2-nitrobenzenesulphenyl)indolenine], hydroxylamine, Staphylococcus aureus V8 proteinase, tryptic and chymotryptic peptides, and by digestion of the protein with carboxypeptidase A. The sequence of the blocked N-terminal tryptic peptide from citraconylated protein was determined by collisionally induced decomposition mass spectrometry. The protein contains 132 amino acid residues, is enriched with respect to threonine and lysine, lacks cysteine, has an acetylated valine residue at the N-terminus, and has an Mr of 14768 and an isoelectric point of 5.25. This protein contains two short internal repeated sequences from residues 48-54 and from residues 114-119 located within regions of predicted beta-structure and decreasing hydrophobicity. These short repeats are contained within two longer repeated regions from residues 48-60 and residues 114-125, which display 62% sequence similarity. These regions could accommodate the charged and uncharged moieties of long-chain fatty acids and may represent fatty acid-binding domains consistent with the finding that human heart fatty acid-binding protein binds 2 mol of oleate or palmitate/mol of protein. Detailed evidence for the amino acid sequences of the peptides has been deposited as Supplementary Publication SUP 50143 (23 pages) at the British Library Lending Division, Boston Spa, Yorkshire LS23 7BQ, U.K., from whom copies may be obtained as indicated in Biochem. J. (1988) 249, 5.

scholarly journals Characterization and amino acid sequence of Neisseria gonorrhoeae dihydrofolate reductase.

1984 ◽  
Vol 259 (19) ◽  
pp. 12291-12298 ◽  
Author(s):  
D P Baccanari ◽  
R L Tansik ◽  
S J Paterson ◽  
D Stone
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Neisseria Gonorrhoeae ◽  
Dihydrofolate Reductase
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