Govardhan C P, Oprian D D
Graduate Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02254.
J Biol Chem. 1994 Mar 4;269(9):6524-7.
Recently, mutations of the active site Lys296 residue in rhodopsin (Lys296-->Glu and Lys296-->Met) have been found as the cause of disease in some patients with autosomal dominant retinitis pigmentosa. In vitro, these mutations result in constitutive activation of the protein. In an effort to develop a potential therapeutic agent for treatment of the disease, we have examined various amine derivatives of 11-cis- and 9-cis-retinal for ability to irreversibly inactivate a related constitutively active mutant, K296G. Three amines were prepared by reductive amination of retinal: 11-cis-retinylpropylamine, 11-cis-retinylamine, and 9-cis-retinylamine. All three compounds inactivated K296G, and the inactivation could not be reversed upon exposure to light. None of the compounds inactivated the wild-type protein. Although the amines were not effective on the naturally occurring retinitis pigmentosa mutants, presumably because of unfavorable steric interactions with the bulky Glu and Met side chains at position 296, the success with K296G makes it highly encouraging that this approach will evolve related compounds that are capable of inactivating the naturally occurring mutants as well.
最近，已发现视紫红质中活性位点赖氨酸296残基的突变（赖氨酸296→谷氨酸和赖氨酸296→甲硫氨酸）是一些常染色体显性视网膜色素变性患者的致病原因。在体外，这些突变导致该蛋白的组成型激活。为了开发一种治疗该疾病的潜在治疗剂，我们研究了11-顺式和9-顺式视黄醛的各种胺衍生物对相关组成型激活突变体K296G进行不可逆失活的能力。通过视黄醛的还原胺化制备了三种胺：11-顺式视黄醛丙胺、11-顺式视黄醛胺和9-顺式视黄醛胺。所有这三种化合物都使K296G失活，并且在光照下失活不能逆转。这些化合物都没有使野生型蛋白失活。尽管这些胺对天然存在的视网膜色素变性突变体无效，推测是因为与296位庞大的谷氨酸和甲硫氨酸侧链存在不利的空间相互作用，但K296G的成功使人们非常鼓舞地认为这种方法将开发出也能够使天然存在的突变体失活的相关化合物。
