Dennis M S, Henzel W J, Bell J, Kohr W, Light D R
Department of Medicinal Biology, Genentech, Inc., South San Francisco, California 94080.
J Biol Chem. 1989 Nov 5;264(31):18618-26.
The amino acid sequence of rubber elongation factor, a recently discovered protein tightly bound to rubber particles isolated from the commercial rubber tree Hevea brasiliensis, is presented. The role of this protein in rubber elongation and its interaction with prenyltransferase and rubber particles have been discussed in the preceding paper in this series (Dennis, M. S., and Light, D. R. (1989) J. Biol. Chem. 264, 18608-18617). Trypsin, Staphylococcus protease, chymotrypsin, acetic acid, and hydroxylamine cleavage were used to generate peptide fragments that were isolated by reverse phase high pressure liquid chromatography and analyzed by amino acid composition and automated Edman degradation. Each digest contained one blocked peptide identified as the amino terminus. The blocked amino-terminal peptide from the tryptic digest was analyzed by amino acid composition, fast atom bombardment mass spectrometry (molecular ion 1659.9), subdigested with Staphylococcus protease for partial sequence analysis, and finally deblocked with bovine liver acyl-peptide hydrolase removing an acetylalanine to allow analysis by Edman degradation. Rubber elongation factor is 137 amino acids long, has a molecular mass of 14,600 daltons, and lacks four amino acids: cysteine, methionine, histidine, and tryptophan. The NH2 terminus is highly charged and contains only acidic residues (5 of the first 12 amino acids). The first four amino acids are highly represented in other known NH2-terminally acetylated proteins. Comparison of the sequence of rubber elongation factor with other known sequences does not reveal significant sequence similarities that would suggest an evolutionary relationship.
本文给出了橡胶延长因子的氨基酸序列，该蛋白是最近发现的一种与从商业橡胶树巴西橡胶树中分离出的橡胶颗粒紧密结合的蛋白质。本系列的前一篇论文（丹尼斯，M.S.，和莱特，D.R.（1989年）《生物化学杂志》264卷，18608 - 18617页）已经讨论了这种蛋白质在橡胶延长中的作用及其与异戊烯基转移酶和橡胶颗粒的相互作用。使用胰蛋白酶、葡萄球菌蛋白酶、胰凝乳蛋白酶、乙酸和羟胺裂解来产生肽片段，这些片段通过反相高压液相色谱分离，并通过氨基酸组成分析和自动埃德曼降解进行分析。每个消化产物都含有一个被鉴定为氨基末端的封闭肽。对胰蛋白酶消化产物中封闭的氨基末端肽进行氨基酸组成分析、快原子轰击质谱分析（分子离子1659.9），用葡萄球菌蛋白酶进行亚消化以进行部分序列分析，最后用牛肝酰基肽水解酶去除乙酰丙氨酸进行去封闭，以便通过埃德曼降解进行分析。橡胶延长因子由137个氨基酸组成，分子量为14,600道尔顿，缺少四种氨基酸：半胱氨酸、甲硫氨酸、组氨酸和色氨酸。氨基末端带电量很高，仅含有酸性残基（前12个氨基酸中有5个）。前四个氨基酸在其他已知的氨基末端乙酰化蛋白质中高度富集。将橡胶延长因子的序列与其他已知序列进行比较，未发现表明进化关系的显著序列相似性。
