BIOMI 2900 Lecture Notes - Lecture 4: Teichoic Acid, Dd-Transpeptidase, Gram-Negative Bacteria

• School: Cornell University
• Department: Microbiology
• Course: BIOMI 2900
• Professor: Daniel Buckley

Document Summary

Water force/pressure can cause cells to explode: the cell wall (rigid) aids in combating this. Cells have very high solute concentration so water tries to get in (cid:2) (cid:2) (cid:2) (cid:2) permeable; like chainmail (provides protection but lets things through) Peptidoglycan = a ridged layer, provides cell shape/strength, Defining characteristic of bacterial cells (all of them have it and no other domains have it) Strands held together by peptide side chains. Polysaccharide backbone containing: l ala, d glu, dap, d-ala, or, l-ala, d-glu, l-lys, d-ala, n acetylglucosamine, n acetylmuramic acid. Has covalent cross links between [dap and d-ala] or [l-lys and d-ala: peptide interbridge in gram positive cells and direct crosslinks in gram negative. Autolysins cut beta -1,4 bonds of polysaccharide backbones so that new polysaccharide can be added: when the cell grows, this helps the peptidoglycan layer. Transpeptidase adds new peptide crosslinks (creating new grow with it bonds) Many antimicrobials target the cell wall (cid:2) (cid:2) (cid:2) (cid:2)