Loose fit: IPNS catalyses the central step in penicillin biosynthesis. Substrate analogues containing L‐homocysteine in place of the natural substrate's L‐cysteine residue are not converted into bicyclic products. Crystal structures for IPNS complexes with two such analogues reveal that the additional CH2 unit affords considerable conformational freedom when these analogues bind to IPNS.
宽松:I
PNS催化
青霉素生物合成的关键步骤。包含
L-高半胱氨酸代替天然底物
L-半胱氨酸残基的底物类似物不会转化为双环产物。具有两个这样的类似物的I
PNS配合物的晶体结构表明,当这些类似物与I
PNS结合时,额外的CH 2单元可提供相当的构象自由度。