Raetz C R, Roderick S L
Department of Biochemistry, Duke University Medical Center, Durham, NC 22710, USA.
Science. 1995 Nov 10;270(5238):997-1000. doi: 10.1126/science.270.5238.997.
UDP-N-acetylglucosamine 3-O-acyltransferase (LpxA) catalyzes the transfer of (R)-3-hydroxymyristic acid from its acyl carrier protein thioester to UDP-N-acetylglucosamine. LpxA is the first enzyme in the lipid A biosynthetic pathway and is a target for the design of antibiotics. The x-ray crystal structure of LpxA has been determined to 2.6 angstrom resolution and reveals a domain motif composed of parallel beta strands, termed a left-handed parallel beta helix (L beta H). This unusual fold displays repeated violations of the protein folding constraint requiring right-handed crossover connections between strands of parallel beta sheets and may be present in other enzymes that share amino acid sequence homology to the repeated hexapeptide motif of LpxA.
UDP-N-乙酰葡糖胺3-O-酰基转移酶（LpxA）催化（R）-3-羟基肉豆蔻酸从其酰基载体蛋白硫酯转移至UDP-N-乙酰葡糖胺。LpxA是脂多糖A生物合成途径中的首个酶，也是抗生素设计的靶点。LpxA的X射线晶体结构已确定至2.6埃分辨率，揭示了一个由平行β链组成的结构域基序，称为左手平行β螺旋（LβH）。这种不同寻常的折叠方式多次违反了蛋白质折叠的限制条件，该条件要求平行β折叠的链之间进行右手交叉连接，并且可能存在于与LpxA的重复六肽基序具有氨基酸序列同源性的其他酶中。
