Alterations in High Molecular Mass Penicillin-Binding Protein 1 Associated with Beta-Lactam Resistance inShigella dysenteriae

1998 ◽  
Vol 248 (3) ◽  
pp. 669-672 ◽  
Author(s):  
Anindya Sundar Ghosh ◽  
Alak Kanti Kar ◽  
Manikuntala Kundu
Keyword(s):  
Molecular Mass ◽  
Binding Protein ◽  
High Molecular Mass ◽  
Penicillin Binding Protein ◽  
Beta Lactam

scholarly journals A mutation in the D,D-carboxypeptidase penicillin-binding protein 3 of Streptococcus pneumoniae contributes to cefotaxime resistance of the laboratory mutant C604.

1997 ◽  
Vol 41 (5) ◽  
pp. 936-942 ◽  
Author(s):  
J Krauss ◽  
R Hakenbeck
Keyword(s):  
Streptococcus Pneumoniae ◽  
Molecular Mass ◽  
Recombination Event ◽  
Binding Protein ◽  
High Molecular Mass ◽  
Penicillin Binding Protein ◽  
Beta Lactam ◽  
Site Specific ◽  
Beta Lactamases ◽  
A Site

Cefotaxime resistance in laboratory mutant C604 of Streptococcus pneumoniae, for which the MIC is 1.5 microg/ml, is independent of alterations in high-molecular-mass penicillin-binding protein (PBP) 1a. Instead, a point mutation in PBP 3, the D,D-carboxypeptidase of this organism, caused a reduced affinity for penicillin and contributed to the decreased susceptibility. The mutation Thr-242 to Ile was located directly adjacent to the triad Lys-239-Thr-Gly, a position known to be important for beta-lactam interaction with high-molecular-mass PBPs and beta-lactamases. This mutation was absent in the PBP 3's of four genetically distinct clinical isolates resistant to high levels of penicillin. None of the pbp3 genes had a mosaic structure, but in three cases there was evidence for a site-specific recombination event within a BOX element immediately downstream of pbp3.

Overexpression, purification and biochemical characterization of a class A high-molecular-mass penicillin-binding protein (PBP), PBP1∗ and its soluble derivative from Mycobacterium tuberculosis

2002 ◽  
Vol 361 (3) ◽  
pp. 635-639
Author(s):  
Sanjib BHAKTA ◽  
Joyoti BASU
Keyword(s):  
Molecular Mass ◽  
Inclusion Bodies ◽  
Biochemical Characterization ◽  
Binding Protein ◽  
High Molecular Mass ◽  
Proteinase K ◽  
Amino Acid Residues ◽  
Penicillin Binding Protein ◽  
E Coli ◽  
Class A

The product of the gene ponA present in cosmid MTCY21D4, one of the collection of clones representing the genome of Mycobacteriumtuberculosis, has been named penicillin-binding protein 1∗ (PBP1∗), by analogy to the previously characterized PBP1∗ of M. leprae. This gene has been overexpressed in Escherichia coli. His6-tagged PBP1∗ localizes to the membranes of induced E. coli cells. Its susceptibility to degradation upon proteinase K digestion of spheroplasts from E. coli expressing the protein supports the view that the majority of the protein translocates to the periplasmic side of the membrane. Recombinant PBP1∗ binds benzylpenicillin and several other β-lactams, notably cefotaxime, with high affinity. Truncation of the N-terminal 64 amino acid residues results in an expressed protein present exclusively in inclusion bodies and unable to associate with the membrane. The C-terminal module encompassing amino acids 272–663 can be extracted from inclusion bodies under denaturing conditions using guanidine/HCl and refolded to give a protein fully competent in penicillin-binding. Deletion of Gly95—Gln143 results in the expression of a protein, which is localized in the cytosol. The soluble derivative of PBP1∗ binds benzylpenicillin with the same efficiency as the full-length protein. This is the first report of a soluble derivative of a class A high-molecular-mass PBP.

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