Moscatelli Alessandra, Scali Monica, Prescianotto-Baschong Cristina, Ferro Myriam, Garin Jerome, Vignani Rita, Ciampolini Fabrizio, Cresti Mauro
Dipartimento di Biologia, Università degli Studi di Milano, Via Celoria 26, 20133, Milano, Italy.
Planta. 2005 Aug;221(6):776-89. doi: 10.1007/s00425-005-1487-7. Epub 2005 Jun 7.
Seven isoforms of 85 kDa polypeptides (p85) were identified as methionine synthase (MetE) homologs by partial aminoacid sequencing in tobacco pollen tube extracts. Immunocytochemistry data showed a localization of the antigen on the surface of tip-focussed post-Golgi secretory vesicles (SVs), that appear to be partially associated with microtubules (Mts). The chemical dissection of pollen tube high speed supernatant (HSS) showed that two distinct pools of MetE are present in pollen tubes, one being the more acidic isoforms sedimenting at 15S and the remaining at 4S after zonal centrifugation through a sucrose density gradient. The identification of the MetE within the pollen tube and its possible participation as methyl donor in a wide range of metabolic reactions, makes it a good subject for studies on pollen tube growth regulation.
通过对烟草花粉管提取物进行部分氨基酸测序，鉴定出七种85 kDa多肽（p85）同工型为甲硫氨酸合酶（MetE）同源物。免疫细胞化学数据显示，抗原定位于高尔基体后分泌小泡（SVs）顶端聚焦的表面，这些小泡似乎部分与微管（Mts）相关。对花粉管高速上清液（HSS）的化学分析表明，花粉管中存在两个不同的MetE池，一个是在通过蔗糖密度梯度进行区带离心后，沉降在15S的酸性更强的同工型，其余的沉降在4S。花粉管中MetE的鉴定及其作为甲基供体可能参与多种代谢反应，使其成为研究花粉管生长调节的良好对象。
