Instruct: Identify the main category of Biorxiv papers based on the titles and abstracts
Query: Heavy isotope labeling and mass spectrometry reveal unexpected remodeling of bacterial cell wall expansion in response to drugs Antibiotics of the {beta}-lactam (penicillin) family inactivate target enzymes called D,D-transpeptidases or penicillin-binding proteins (PBPs) that catalyze the last cross-linking step of peptidoglycan synthesis. The resulting net-like macromolecule is the essential component of bacterial cell walls that sustains the osmotic pressure of the cytoplasm. In Escherichia coli, bypass of PBPs by the YcbB L,D-transpeptidase leads to resistance to these drugs. We developed a new method based on heavy isotope labeling and mass spectrometry to elucidate PBP- and YcbB-mediated peptidoglycan polymerization. PBPs and YcbB similarly participated in single-strand insertion of glycan chains into the expanding bacterial side wall. This absence of any transpeptidase-specific signature suggests that the peptidoglycan expansion mode is determined by other components of polymerization complexes. YcbB did mediate {beta}-lactam resistance by insertion of multiple strands that were exclusively cross-linked to existing tripeptide-containing acceptors. We propose that this unprecedented mode of polymerization depends upon accumulation of linear glycan chains due to PBP inactivation, formation of tripeptides due to cleavage of existing cross-links by a {beta}-lactam-insensitive endopeptidase, and concerted cross-linking by YcbB.
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The categories of this paper are: systems
14
The categories of this paper are: biophysics
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The categories of this paper are: genomics
2
The categories of this paper are: biology
30
The categories of this paper are: scientific
23
The categories of this paper are: immunology
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The categories of this paper are: communication
22
The categories of this paper are: physiology
6
The categories of this paper are: plant
7
The categories of this paper are: ecology
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The categories of this paper are: developmental
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The categories of this paper are: microbiology
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The categories of this paper are: paleontology
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The categories of this paper are: zoology
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The categories of this paper are: pharmacology
3
The categories of this paper are: evolutionary