Molina A, Segura A, García-Olmedo F
Laboratorio de Bioquímica y Biología Molecular, ETS Ingenieros Agrónomos-UPM, Madrid, Spain.
FEBS Lett. 1993 Jan 25;316(2):119-22. doi: 10.1016/0014-5793(93)81198-9.
Four homogeneous proteins (Cw18, Cw20, Cw21, Cw22) were isolated from etiolated barley leaves by extraction of the insoluble pellet from a Tris-HCl (pH 7.5) homogenate with 1.5 M LiCl and fractionation by reverse-phase high-performance liquid chromatography. All 4 proteins inhibited growth of the pathogen Clavibacter michiganensis subsp. sepedonicus (EC50s = 1-3 x 10(-7) M) and had closely related N-terminal amino acid sequences. The complete amino acid sequences of proteins Cw18 and Cw21 were determined and found to be homologous to previously described, non-specific lipid transfer proteins from plants (32-62% identical positions). The proteins also inhibited growth of the bacterial pathogen Pseudomonas solanacearum (EC50s = 3-6 x 10(-7) M) and the fungus Fusarium solani (EC50s = 3-20 x 10(-6) M). A homologous protein from maize leaves (Cw41) was purified in a similar manner and also found to have inhibitory properties. A synergistic effect against the fungus was observed when protein Cw21 was combined with thionins. A defense role for non-specific lipid transfer proteins from plants is proposed.
通过用1.5M LiCl从Tris-HCl（pH 7.5）匀浆的不溶性沉淀中提取，并经反相高效液相色谱分级分离，从黄化大麦叶片中分离出四种同源蛋白（Cw18、Cw20、Cw21、Cw22）。所有这4种蛋白均抑制病原菌密歇根棒杆菌番茄溃疡病菌亚种的生长（半数有效浓度=1-3×10⁻⁷M），且具有密切相关的N端氨基酸序列。测定了蛋白Cw18和Cw21的完整氨基酸序列，发现它们与先前描述的植物非特异性脂质转移蛋白同源（相同位置的同源性为32-62%）。这些蛋白还抑制细菌病原菌青枯假单胞菌的生长（半数有效浓度=3-6×10⁻⁷M）和真菌茄病镰刀菌的生长（半数有效浓度=3-20×10⁻⁶M）。以类似方式纯化了来自玉米叶片的一种同源蛋白（Cw41），发现其也具有抑制特性。当蛋白Cw21与硫堇结合时，观察到对该真菌的协同作用。提出了植物非特异性脂质转移蛋白的防御作用。
