Mizutani Kohei, Hirasawa Yusuke, Sugita-Konishi Yoshiko, Mochizuki Naoki, Morita Hiroshi
Asahi Breweries, Ltd, Moriya, Ibaraki, Japan.
J Nat Prod. 2008 Jul;71(7):1297-300. doi: 10.1021/np800150m. Epub 2008 Jun 18.
A new chlorinated cyclic pentapeptide, hydroxycyclochlorotine (1), has been isolated from Penicillium islandicum, and the structure including absolute stereochemistry of 1 and conformational properties of 1 and cyclochlorotine (2) in DMSO-d6 were elucidated by using extensive 2D NMR and chemical means. Hydroxycyclochlorotine (1) and astin B (3) from Aster tataricus, each containing an allo threonine at residue 2, have a cis proline configuration, whereas cyclochlorotine (2) has two conformational states in solution, which may be produced from cis-trans isomerization of the proline amide bond. The presence of an intramolecular hydrogen bond between Ser (3)-NH and a hydroxyl oxygen atom of alloThr (2) may serve to maintain the backbone conformation with a cis proline amide bond.
从冰岛青霉中分离出一种新的氯化环五肽——羟基环氯素（1），并通过广泛的二维核磁共振和化学方法阐明了其结构，包括1的绝对立体化学以及1和环氯素（2）在氘代二甲亚砜中的构象性质。来自紫菀的羟基环氯素（1）和紫菀宁B（3）在残基2处均含有别苏氨酸，具有顺式脯氨酸构型，而环氯素（2）在溶液中有两种构象状态，这可能是由脯氨酸酰胺键的顺反异构化产生的。丝氨酸（3）-NH与别苏氨酸（2）的羟基氧原子之间存在分子内氢键，可能有助于维持具有顺式脯氨酸酰胺键的主链构象。
