Raymond-Denise A, Sansonetti P, Guillén N
Unité de Pathogénie Microbienne Moléculaire, U199 INSERM, Institut Pasteur, Paris, France.
Mol Biochem Parasitol. 1993 May;59(1):123-31. doi: 10.1016/0166-6851(93)90013-n.
The mhcA gene from the human pathogen Entamoeba histolytica was identified using the polymerase chain reaction. It is a single copy gene expressed as a 6.4-kb mRNA. The deduced MhcA protein sequence is highly similar to myosin II from both Dictyostelium discoideum and Acanthamoeba castellanii. The globular head domain of MhcA contains the specific regions involved in ATP binding, actin binding, and interaction with myosin light chain. The tail domain is organized in an alpha-helical coiled coil structure, which suggests that MhcA is an alpha-fibrous protein. The coiled coil is interrupted by two prolines indicating that like other myosins, either from smooth muscle or from non-muscle cells, the tail of MhcA folds twice on itself. In addition, MhcA presents sequence similarities with the heavy chain phosphorylation sites of smooth and non-muscle vertebrate myosins.
利用聚合酶链反应鉴定了人类病原体溶组织内阿米巴的mhcA基因。它是一个单拷贝基因，表达为6.4 kb的mRNA。推导的MhcA蛋白序列与盘基网柄菌和卡氏棘阿米巴的肌球蛋白II高度相似。MhcA的球状头部结构域包含参与ATP结合、肌动蛋白结合以及与肌球蛋白轻链相互作用的特定区域。尾部结构域呈α螺旋卷曲螺旋结构，这表明MhcA是一种α纤维蛋白。卷曲螺旋被两个脯氨酸打断，这表明与其他肌球蛋白一样，无论是平滑肌还是非肌肉细胞来源的，MhcA的尾部自身折叠两次。此外，MhcA与平滑肌和非肌肉脊椎动物肌球蛋白的重链磷酸化位点存在序列相似性。
