scholarly journals Mutant isolation and molecular cloning of mre genes, which determine cell shape, sensitivity to mecillinam, and amount of penicillin-binding proteins in Escherichia coli.

1987 ◽  
Vol 169 (11) ◽  
pp. 4935-4940 ◽  
Author(s):  
M Wachi ◽  
M Doi ◽  
S Tamaki ◽  
W Park ◽  
S Nakajima-Iijima ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Molecular Cloning ◽  
Cell Shape ◽  
Binding Proteins ◽  
Shape Sensitivity ◽  
Penicillin Binding Proteins ◽  
Mutant Isolation

scholarly journals Contributions of PBP 5 anddd-Carboxypeptidase Penicillin Binding Proteins to Maintenance of Cell Shape in Escherichia coli

2001 ◽  
Vol 183 (10) ◽  
pp. 3055-3064 ◽  
Author(s):  
David E. Nelson ◽  
Kevin D. Young
Keyword(s):  
Escherichia Coli ◽  
Cell Shape ◽  
Binding Proteins ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Morphological Defects ◽  
Membrane Anchoring ◽  
Binding Sequence

ABSTRACT Escherichia coli has 12 recognized penicillin binding proteins (PBPs), four of which (PBPs 4, 5, and 6 and DacD) havedd-carboxypeptidase activity. Although the enzymology of the dd-carboxypeptidases has been studied extensively, the in vivo functions of these proteins are poorly understood. To explain why E. coli maintains four independent loci encoding enzymes of considerable sequence identity and comparable in vitro activity, it has been proposed that thedd-carboxypeptidases may substitute for one another in vivo. We tested the validity of this equivalent substitution hypothesis by investigating the effects of these proteins on the aberrant morphology of ΔdacA mutants, which produce no PBP 5. Although cloned PBP 5 complemented the morphological phenotype of a ΔdacA mutant lacking a total of seven PBPs, controlled expression of PBP 4, PBP 6, or DacD did not. Also, a truncated PBP 5 protein lacking its amphipathic C-terminal membrane binding sequence did not reverse the morphological defects and was lethal at low levels of expression, implying that membrane anchoring is essential for the proper functioning of PBP 5. By examining a set of mutants from which multiple PBP genes were deleted, we found that significant morphological aberrations required the absence of at least three different PBPs. The greatest defects were observed in cells lacking, at minimum, PBPs 5 and 6 and one of the endopeptidases (either PBP 4 or PBP 7). The results further differentiate the roles of the low-molecular-weight PBPs, suggest a functional significance for the amphipathic membrane anchor of PBP 5 and, when combined with the recently determined crystal structure of PBP 5, suggest possible mechanisms by which these PBPs may contribute to maintenance of a uniform cell shape in E. coli.

scholarly journals FtsZ Collaborates with Penicillin Binding Proteins To Generate Bacterial Cell Shape in Escherichia coli

2004 ◽  
Vol 186 (20) ◽  
pp. 6768-6774 ◽  
Author(s):  
Archana Varma ◽  
Kevin D. Young
Keyword(s):  
Escherichia Coli ◽  
Cell Shape ◽  
Binding Proteins ◽  
Structural Integrity ◽  
Morphological Diversity ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Penicillin Binding Proteins ◽  
Bacterial Cell Shape ◽  
Defective Sites

ABSTRACT The mechanisms by which bacteria adopt and maintain individual shapes remain enigmatic. Outstanding questions include why cells are a certain size, length, and width; why they are uniform or irregular; and why some branch while others do not. Previously, we showed that Escherichia coli mutants lacking multiple penicillin binding proteins (PBPs) display extensive morphological diversity. Because defective sites in these cells exhibit the structural and functional characteristics of improperly localized poles, we investigated the connection between cell division and shape. Here we show that under semipermissive conditions the temperature-sensitive FtsZ84 protein produces branched and aberrant cells at a high frequency in mutants lacking PBP 5, and this phenotype is exacerbated by the loss of additional peptidoglycan endopeptidases. Surprisingly, certain ftsZ84 strains lyse at the nonpermissive temperature instead of filamenting, and inhibition of wild-type FtsZ forces some mutants into tightly wound spirillum-like morphologies. The results demonstrate that significant aspects of bacterial shape are dictated by a previously unrecognized relationship between the septation machinery and ostensibly minor peptidoglycan-modifying enzymes and that under certain circumstances improper FtsZ function can destroy the structural integrity of the cell.

scholarly journals Enterobactin- and salmochelin-β-lactam conjugates induce cell morphologies consistent with inhibition of penicillin-binding proteins in uropathogenic Escherichia coli CFT073

2021 ◽  
Author(s):  
Artur Sargun ◽  
Timothy C. Johnstone ◽  
Hui Zhi ◽  
Manuela Raffatellu ◽  
Elizabeth M. Nolan
Keyword(s):  
Escherichia Coli ◽  
Binding Proteins ◽  
Uropathogenic Escherichia Coli ◽  
Penicillin Binding Proteins ◽  
E Coli

Siderophore-β-lactam conjugates based on enterobactin and diglucosylated enterobactin enter the periplasm of uropathogenic E. coli CFT073 via the FepA and IroN transporters, and target penicillin-binding proteins.

The use of a Mercury-Penicillin V Derivative to Localize Penicillin-Binding Proteins in Escherichia coli

1993 ◽  
pp. 295-301
Author(s):  
Terry R. Paul ◽  
Terry J. Beveridge ◽  
Noreen G. Halligan ◽  
Larry C. Blaszczak ◽  
Tom R. Parr
Keyword(s):  
Escherichia Coli ◽  
Binding Proteins ◽  
Penicillin Binding Proteins ◽  
Penicillin V

scholarly journals Escherichia coli Mutants Lacking All Possible Combinations of Eight Penicillin Binding Proteins: Viability, Characteristics, and Implications for Peptidoglycan Synthesis

1999 ◽  
Vol 181 (13) ◽  
pp. 3981-3993 ◽  
Author(s):  
Sylvia A. Denome ◽  
Pamela K. Elf ◽  
Thomas A. Henderson ◽  
David E. Nelson ◽  
Kevin D. Young
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Binding Proteins ◽  
Kanamycin Resistance ◽  
Open Reading Frames ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Peptidoglycan Biosynthesis ◽  
Kanamycin Resistance Cassette ◽  
Genes Encoding

ABSTRACT The penicillin binding proteins (PBPs) synthesize and remodel peptidoglycan, the structural component of the bacterial cell wall. Much is known about the biochemistry of these proteins, but little is known about their biological roles. To better understand the contributions these proteins make to the physiology ofEscherichia coli, we constructed 192 mutants from which eight PBP genes were deleted in every possible combination. The genes encoding PBPs 1a, 1b, 4, 5, 6, and 7, AmpC, and AmpH were cloned, and from each gene an internal coding sequence was removed and replaced with a kanamycin resistance cassette flanked by two ressites from plasmid RP4. Deletion of individual genes was accomplished by transferring each interrupted gene onto the chromosome of E. coli via λ phage transduction and selecting for kanamycin-resistant recombinants. Afterwards, the kanamycin resistance cassette was removed from each mutant strain by supplying ParA resolvase in trans, yielding a strain in which a long segment of the original PBP gene was deleted and replaced by an 8-bpres site. These kanamycin-sensitive mutants were used as recipients in further rounds of replacement mutagenesis, resulting in a set of strains lacking from one to seven PBPs. In addition, thedacD gene was deleted from two septuple mutants, creating strains lacking eight genes. The only deletion combinations not produced were those lacking both PBPs 1a and 1b because such a combination is lethal. Surprisingly, all other deletion mutants were viable even though, at the extreme, 8 of the 12 known PBPs had been eliminated. Furthermore, when both PBPs 2 and 3 were inactivated by the β-lactams mecillinam and aztreonam, respectively, several mutants did not lyse but continued to grow as enlarged spheres, so that one mutant synthesized osmotically resistant peptidoglycan when only 2 of 12 PBPs (PBPs 1b and 1c) remained active. These results have important implications for current models of peptidoglycan biosynthesis, for understanding the evolution of the bacterial sacculus, and for interpreting results derived by mutating unknown open reading frames in genome projects. In addition, members of the set of PBP mutants will provide excellent starting points for answering fundamental questions about other aspects of cell wall metabolism.

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