Peptidoglycan: Difference between revisions
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Peptidoglycan is found in both | Peptidoglycan is found in both <a href="Gram-negative">Gram-negative</a> and <a href="Gram-positive">Gram-positive</a> <a href="Bacteria">bacteria</a>. It is present in larger amounts in Gram-positive bacteria as it appears as a multimolecular layer and can be found in association with additional compounds. In Gram-negative bacteria, it is found in either 1 or 2 layers between the inner and outer membrane<ref>http://www.chem.qmul.ac.uk/iupac/misc/glycp.html#3.9</ref>. | ||
Peptidoglycan is a | Peptidoglycan is a <a href="Macromolecule">macromolecule</a> made up of alternating <a href="Residues">residues</a> of <a href="N-acetyl-β-D-glucosamine">N-acetyl-β-D-glucosamine</a> (NAG) and <a href="N-acetylmuramic acid">N-acetylmuramic acid</a> (NAM) joined together by a <a href="Glycosidic bond">glycosidic bond</a><ref>http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit1/prostruct/cw.html</ref>. There is then a <a href="Pentapeptide">pentapeptide</a> attached to the NAM amino acid which forms cross-links with other polysaccharide chains forming a 3D mesh-like layer. These cross-links are formed using the enzyme <a href="Glycopeptide transpeptidase">glycopeptide transpeptidase</a> and provide peptidoglycan with stability. This stability allows it to provide mechanical support and prevent osmotic lysis from occurring in bacteria<ref>Berg J., Tymoczko J and Stryer L. (2012) Biochemistry, 7th edition, New York: WH Freeman: pg 252</ref>. | ||
<a href="Penicillin">Penicillin</a> <a href="Inhibits">inhibits</a> the effect of peptidoglycan in bacteria by binding to <a href="Serine">serine</a> in the enzyme <a href="Glycopeptide transpeptidase">glycopeptide transpeptidase</a>. As a result, it can no longer catalyse the formation of cross-links. The enzyme is irreversibly inhibited which therefore results in the termination of bacterial growth<ref>http://www.ncbi.nlm.nih.gov/books/NBK7986/</ref>. | |||
Penicillin inhibits the transpeptidase linking together the polysaccharide chains and cells become osmotically sensitive and burst. | Penicillin inhibits the transpeptidase linking together the polysaccharide chains and cells become osmotically sensitive and burst. | ||
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=== References === | === References === | ||
<span class="fck_mw_references" _fck_mw_customtag="true" _fck_mw_tagname="references" /> | |||
Revision as of 16:17, 17 October 2018
Peptidoglycan is found in both <a href="Gram-negative">Gram-negative</a> and <a href="Gram-positive">Gram-positive</a> <a href="Bacteria">bacteria</a>. It is present in larger amounts in Gram-positive bacteria as it appears as a multimolecular layer and can be found in association with additional compounds. In Gram-negative bacteria, it is found in either 1 or 2 layers between the inner and outer membrane[1].
Peptidoglycan is a <a href="Macromolecule">macromolecule</a> made up of alternating <a href="Residues">residues</a> of <a href="N-acetyl-β-D-glucosamine">N-acetyl-β-D-glucosamine</a> (NAG) and <a href="N-acetylmuramic acid">N-acetylmuramic acid</a> (NAM) joined together by a <a href="Glycosidic bond">glycosidic bond</a>[2]. There is then a <a href="Pentapeptide">pentapeptide</a> attached to the NAM amino acid which forms cross-links with other polysaccharide chains forming a 3D mesh-like layer. These cross-links are formed using the enzyme <a href="Glycopeptide transpeptidase">glycopeptide transpeptidase</a> and provide peptidoglycan with stability. This stability allows it to provide mechanical support and prevent osmotic lysis from occurring in bacteria[3].
<a href="Penicillin">Penicillin</a> <a href="Inhibits">inhibits</a> the effect of peptidoglycan in bacteria by binding to <a href="Serine">serine</a> in the enzyme <a href="Glycopeptide transpeptidase">glycopeptide transpeptidase</a>. As a result, it can no longer catalyse the formation of cross-links. The enzyme is irreversibly inhibited which therefore results in the termination of bacterial growth[4].
Penicillin inhibits the transpeptidase linking together the polysaccharide chains and cells become osmotically sensitive and burst.
References
<span class="fck_mw_references" _fck_mw_customtag="true" _fck_mw_tagname="references" />
- ↑ http://www.chem.qmul.ac.uk/iupac/misc/glycp.html#3.9
- ↑ http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit1/prostruct/cw.html
- ↑ Berg J., Tymoczko J and Stryer L. (2012) Biochemistry, 7th edition, New York: WH Freeman: pg 252
- ↑ http://www.ncbi.nlm.nih.gov/books/NBK7986/