Praeteritis decem annis, investigatio de endotoxin maxime in biosynthesi viae E. coli K-12 lipidorum feruntur.

In processu superficiei cellae biosynthesis, UDP-N-acetylglucosaminum (UDP-GlcNAc) est momenti intermedius et communis praecursor peptidoglycanorum et lipidorum A, quae in synthesi superficiei polysaccharidis magnas partes agit. In LPS nucleus polysaccharides et О CleNAc partes praecipuas habent in obligatione antigenii.

UDP-GlcN et β- Acidum hydroxytetradecanoicum . β- Praecursor moleculae lipidi A synthesis, ut hydroxy myristoyl-acyl tabellarius interdum, hydroxy myristoyl-ACP), lipidorum A generant per reactiones sequentem seriem:

1. Formatio UDP - monoacyl acetylglucosamine

UDP-GlcNAc est β- Hydroxytetradecanoico-apolipoprotein β Acidum hydroxytetradecanoicum acylationem generat UDP-3-monoacyl-GleNAc. Haec reactio catalyzed ab acyltransferase. Lax A gene ad 4 minuta chromosomatum encodes acyltransferas sita est.

2. Productio UDP-2, 3-diacylis glucosaminum et lipidorum X

UDP-monoacyl acetylglucosamine deacetylated in globus amino sub catalysi N-deacetylase ab lpxC gene encoded et dein ad amino globi transfertur sub catalysin producti a lpxD gene aba- hydroxytetradecanoico, glucosamine diacyl producente. (UDP - 2, 3 - diacyl - GlcN). UDP of UDP-lipoacylglucosum tollitur a pyrophosphatase ad producendum 1-phosphos-2,3-dilipoacylglucosamine, quod vulgo lipidi X (lipidi x).

3. Formatio lipidorum a

UDP-2, 3-diacyl glucosaminum, et lipidorum X per aba transeunt. 1,6 Vinculum pyrophosphatum connectitur et condensatur ad sceletum lipidi formandum. Hoc tempore, sunt 2 in unaquaque saccharo coetus aba. Hydroxytetradecanoicum acidum, glucosaminum reducens, globulum phosphas ad locum C-1 habet. Haec reactio catalyzed a dapibus encoded a gene lpxB. Tum, sub catalysi kinasi specificae, positione glucosamine non minuente C-4' phosphorylated est, ut 1,4' - diphosphate tetradecyl glucosamine disaccharide, nempe lipido Ⅳ a (lipido Ⅳ a).

4. Productio lipidorum A

Transitus ab lipidorum Ⅳ a ad lipidorum A additio KDO in situ glucosamine C-6 non reducendo requirit, ac deinde additis duobus acidis saturatioribus pingue et aggregatis polaris ut phosphatis. Mechanismus specifica huius reactionis adhuc lateat.