2.02012-07-30 14:54:39 -06002015-06-03 17:20:39 -0600ECMDB21111M2MDB0015201,6-Anhydrous-N-Acetylmuramyl-tetrapeptide1,6-Anhydrous-N-Acetylmuramyl-tetrapeptide is an intermediate in peptidoglycan synthesis and turnover. Peptidoglycan can be described as a fisherman's net that encloses bacteria. The mesh of the net is made of two segments of parallel, somewhat inextensible glycan threads, held together by two small elastic peptide crosslinks allowing the net to expand or shrink. The glycan moiety of the peptidoglycan is very uniform among all bacteria, and is made up of alternating β-1,4-linked N-acetylglucosamine and N-acetyl muramate residues, with an average chain lengthof 10 to 65 disaccharide units (depending on the organism). The peptidoglycan synthesis pathway starts in the cytoplasm, where in six steps the peptidoglycan precursor a UDP-N-acetylmuramoyl-pentapeptide is synthesized. This precursor is then attached to the memberane acceptor all-trans-undecaprenyl phosphate, generating a N-acetylmuramoyl-pentapeptide-diphosphoundecaprenol, also known as lipid I. Another transferase then adds UDP-N-acetyl-α-D-glucosamine, yielding the complete monomeric unit a lipid II, also known as lipid II. This final lipid intermediate is transferred by an as yet unknown mechanism through the membrane. The peptidoglycan monomers are then polymerized on the outside surface by glycosyltransferases, which form the linear glycan chains, and transpeptidases, which catalyze the formation of peptide crosslinks. Peptide crosslinks form between different parts of the peptides depending on the organism. For example, in Mycobacteria and in E. coli most links form between the carboxyl group of the penultimate D-alanine (residue 4) of one peptide to the amino group at the D-center of meso-diaminopimelate (residue 3) of an adjacent peptide of a second glycan chain (as in E. coli). The crosslinking reaction is catalyzed by transpeptidases and involves the cleavage of the D-alanyl-D-alanine bond of the donor peptide, providing the energy to drive the reaction. As a result, the peptides in the peptidoglycan polymers are one or two amino acids shorter than the peptides in the monomers.C29H48N6O15720.7226720.317764896(6S)-2-amino-6-{[(2R)-4-carboxy-1-hydroxy-2-{[(2S)-1-hydroxy-2-{[(2R)-1-hydroxy-2-{[(2R,3S,4R,5S)-3-hydroxy-5-[(1-hydroxyethylidene)amino]-2-(hydroxymethyl)oxan-4-yl]oxy}propylidene]amino}propylidene]amino}butylidene]amino}-6-[(1-carboxyethyl)-C-hydroxycarbonimidoyl]hexanoic acid(6S)-2-amino-6-{[(2R)-4-carboxy-1-hydroxy-2-{[(2S)-1-hydroxy-2-{[(2R)-1-hydroxy-2-{[(2R,3S,4R,5S)-3-hydroxy-5-[(1-hydroxyethylidene)amino]-2-(hydroxymethyl)oxan-4-yl]oxy}propylidene]amino}propylidene]amino}butylidene]amino}-6-[(1-carboxyethyl)-C-hydroxycarbonimidoyl]hexanoic acid[H]C(N)(CCC[C@]([H])(N=C(O)[C@@]([H])(CCC(O)=O)N=C(O)[C@]([H])(C)N=C(O)[C@@]([H])(C)O[C@@]1([H])[C@]([H])(O)[C@@]([H])(CO)OC[C@]1([H])N=C(C)O)C(O)=NC([H])(C)C(O)=O)C(O)=OInChI=1S/C29H48N6O15/c1-12(31-25(42)14(3)50-23-19(33-15(4)37)11-49-20(10-36)22(23)40)24(41)34-18(8-9-21(38)39)27(44)35-17(7-5-6-16(30)29(47)48)26(43)32-13(2)28(45)46/h12-14,16-20,22-23,36,40H,5-11,30H2,1-4H3,(H,31,42)(H,32,43)(H,33,37)(H,34,41)(H,35,44)(H,38,39)(H,45,46)(H,47,48)/t12-,13?,14+,16?,17-,18+,19-,20+,22+,23+/m0/s1OUWAMZWZTFUVMV-NPLPHQDTSA-NCytosollogp-1.59logs-3.78solubility1.19e-01 g/llogp-3.4pka_strongest_acidic1.74pka_strongest_basic9.53iupac(6S)-2-amino-6-{[(2R)-4-carboxy-1-hydroxy-2-{[(2S)-1-hydroxy-2-{[(2R)-1-hydroxy-2-{[(2R,3S,4R,5S)-3-hydroxy-5-[(1-hydroxyethylidene)amino]-2-(hydroxymethyl)oxan-4-yl]oxy}propylidene]amino}propylidene]amino}butylidene]amino}-6-[(1-carboxyethyl)-C-hydroxycarbonimidoyl]hexanoic acidaverage_mass720.7226mono_mass720.317764896smiles[H]C(N)(CCC[C@]([H])(N=C(O)[C@@]([H])(CCC(O)=O)N=C(O)[C@]([H])(C)N=C(O)[C@@]([H])(C)O[C@@]1([H])[C@]([H])(O)[C@@]([H])(CO)OC[C@]1([H])N=C(C)O)C(O)=NC([H])(C)C(O)=O)C(O)=OformulaC29H48N6O15inchiInChI=1S/C29H48N6O15/c1-12(31-25(42)14(3)50-23-19(33-15(4)37)11-49-20(10-36)22(23)40)24(41)34-18(8-9-21(38)39)27(44)35-17(7-5-6-16(30)29(47)48)26(43)32-13(2)28(45)46/h12-14,16-20,22-23,36,40H,5-11,30H2,1-4H3,(H,31,42)(H,32,43)(H,33,37)(H,34,41)(H,35,44)(H,38,39)(H,45,46)(H,47,48)/t12-,13?,14+,16?,17-,18+,19-,20+,22+,23+/m0/s1inchikeyOUWAMZWZTFUVMV-NPLPHQDTSA-Npolar_surface_area359.79refractivity167.06polarizability71.19rotatable_bond_count21acceptor_count21donor_count11physiological_charge-1formal_charge0D-Alanine metabolismL-alanine is an essential component of protein and peptidoglycan. The latter also contains about three molecules of D-alanine for every L-alanine. Only about 10 percent of the total alanine synthesized flows into peptidoglycan.
Refer to L-alanine metabolism (pathway PW000788 ).
Through this single pathway D-alanine can be degraded to pyruvate through a D-amino acid dehydrogenase, which enters central metabolism and thereby can serve as a total source of carbon and energy. This pathway is unique among those through which L-amino acids are degraded, in that the L form must first be converted to the D form. This first step of the pathway, which can be catalyzed by either of two racemases( biosynthetic or catabolic), also serves an essential role in biosynthesis because its product, D-alanine, is an essential component of cell wall peptidoglycan (murein). D-alanine is metabolized by an ATP driven D-alanine ligase A and B resulting in D-alanyl-D-alanine. This product is incorporated into the peptidoglycan biosynthesis.
PW000768ec00473MetabolicSpecdb::CMs1083705Specdb::EiMs5508Specdb::NmrOneD249008Specdb::NmrOneD249009Specdb::NmrOneD249010Specdb::NmrOneD249011Specdb::NmrOneD249012Specdb::NmrOneD249013Specdb::NmrOneD249014Specdb::NmrOneD249015Specdb::NmrOneD249016Specdb::NmrOneD249017Specdb::NmrOneD249018Specdb::NmrOneD249019Specdb::NmrOneD249020Specdb::NmrOneD249021Specdb::NmrOneD249022Specdb::NmrOneD249023Specdb::NmrOneD249024Specdb::NmrOneD249025Specdb::NmrOneD249026Specdb::NmrOneD249027Specdb::MsMs27770Specdb::MsMs27771Specdb::MsMs27772Specdb::MsMs34328Specdb::MsMs34329Specdb::MsMs3433046173341CPD0-2285Beta-hexosaminidaseP75949NAGZ_ECOLInagZhttp://ecmdb.ca/proteins/P75949.xmlMurein tetrapeptide carboxypeptidaseP76008LDCA_ECOLIldcAhttp://ecmdb.ca/proteins/P76008.xml1,6-anhydro-N-acetylmuramyl-L-alanine amidase AmpDP13016AMPD_ECOLIampDhttp://ecmdb.ca/proteins/P13016.xml1,6-Anhydrous-N-Acetylmuramyl-tetrapeptide + Water > L-Alanine-D-glutamate-meso-2,6-diaminoheptanedioate-D-alanine + 1,6-Anhydro-N-acetylmuramateN-Acetyl-D-glucosamine(anhydrous)N-Acetylmuramyl-tetrapeptide + Water > N-Acetyl-D-glucosamine + 1,6-Anhydrous-N-Acetylmuramyl-tetrapeptide1,6-Anhydrous-N-Acetylmuramyl-tetrapeptide + Water > D-Alanine + 1,6-Anhydrous-N-Acetylmuramyl-tripeptide