Department of Chemistry, College of the Holy Cross, Worcester, MA 01610, USA.
J Bacteriol. 2011 Feb;193(4):994-7. doi: 10.1128/JB.01287-10. Epub 2010 Dec 3.
A Thermobifida fusca intein has two characteristics of class 3 inteins: a noncontiguous covariant Trp-Cys-Thr triplet and a Ser flanking its C terminus. However, it has Cys at position one, characteristic of class 1 inteins. Splicing does not require the internal Cys, which may instead coordinate the active site. Therefore, the intein is class 1.
热毁栖热菌内含肽具有 3 类内含肽的两个特征:不连续共变的色氨酸-半胱氨酸-苏氨酸三联体和其 C 末端侧翼的丝氨酸。然而,它在位置 1 具有半胱氨酸,这是 1 类内含肽的特征。剪接不需要内部的半胱氨酸,它可能反而协调活性位点。因此,该内含肽是 1 类。