Mtwisha L, Brandt W, McCready S, Lindsey G G
Department of Biochemistry, University of Cape Town, Private Bag, Rondebosch, South Africa.
Plant Mol Biol. 1998 Jun;37(3):513-21. doi: 10.1023/a:1005904219201.
LEA group I, II and III antibodies all recognised soluble proteins present in an extract of yeast (Saccharomyces cerevisiae). The smaller protein of the two recognised by the group I antibody displayed identical migration on SDS-PAGE to the pea seed LEA group I protein against which the antibody was raised. However, the antibody failed to recognise the predominant protein present after heating the extract at 80 degrees C for 10 min. This predominant protein, which also displayed identical migration on SDS-PAGE, was purified from the supernatant of the extract heated at 80 degrees C for 10 min. Peptide sequencing after CNBr cleavage identified the isolated protein as the heat shock protein HSP 12. Despite a previous report that HSP 12 is a heat shock protein, HSP 12 was found to increase in yeast grown at 37 degrees C compared with growth at 30 degrees C. However, increased amounts of HSP 12 were present in yeast after entry into stationary phase; this was enhanced by growth in the osmolytes NaCl and mannitol.
第I、II和III组胚胎晚期丰富（LEA）蛋白抗体均能识别酵母（酿酒酵母）提取物中存在的可溶性蛋白。第I组抗体识别的两种较小蛋白质之一，在SDS-PAGE上的迁移情况与该抗体所针对的豌豆种子第I组LEA蛋白相同。然而，在80℃加热提取物10分钟后，该抗体无法识别提取物中存在的主要蛋白质。这种主要蛋白质在SDS-PAGE上也显示出相同的迁移情况，它是从80℃加热10分钟的提取物上清液中纯化得到的。经溴化氰裂解后的肽段测序确定分离出的蛋白质为热休克蛋白HSP 12。尽管之前有报道称HSP 12是一种热休克蛋白，但研究发现，与在30℃生长的酵母相比，在37℃生长的酵母中HSP 12含量增加。然而，进入稳定期后，酵母中HSP 12的含量会增加；在渗透压调节剂氯化钠和甘露醇中生长会增强这种增加。
