Aarstad K, Zimmer T L, Laland S G
Eur J Biochem. 1980 Nov;112(2):335-8. doi: 10.1111/j.1432-1033.1980.tb07209.x.
The amino acid analog L-cyclohexylalanine, which may be considered an analog of the hydrophobic amino acids leucine and valine, was found to thioester-bind to the heavy enzyme of gramicidin S synthetase. The results indicate that it preferably binds to the thiol site of leucine, although binding to the valine site also occurs. In the synthesis of the cyclic decapeptide by gramicidin S synthetase, the results suggest that L-cyclohexylalanine can replace L-leucine and L-valine. We have also found that in the synthesis of the cyclic decapeptidase L-leucine can replace L-valine and vice versa. The results further indicate that the previously reported thioester binding of D and L-phenylalanine to the heavy enzyme takes place at the thiol site of leucine.
氨基酸类似物L-环己基丙氨酸可被视为疏水氨基酸亮氨酸和缬氨酸的类似物，已发现它能以硫酯形式结合到短杆菌肽S合成酶的重酶上。结果表明，它优先结合到亮氨酸的巯基位点，不过也会与缬氨酸位点结合。在短杆菌肽S合成酶合成环十肽的过程中，结果表明L-环己基丙氨酸可以替代L-亮氨酸和L-缬氨酸。我们还发现，在合成环十肽时，L-亮氨酸可以替代L-缬氨酸，反之亦然。结果进一步表明，先前报道的D-和L-苯丙氨酸与重酶的硫酯结合发生在亮氨酸的巯基位点。
