The approximately 3.5 MDa hexagonal bilayer (HBL) hemoglobin (Hb) of the earthworm Lumbricus terrestris is composed of monomers and disulfide-bonded trimers (T) of globin chains and of four types of heme-deficient linker chains (L). Cryoelectron microscopic images of native Hb and of HBL reassembled from the constituent subunits depleted in monomer subunit (HBL[T+L]) were subjected to three-dimensional reconstructions by the random conical tilt series method. Native Hb has an architecture very similar to those of other annelid and vestimentiferan Hbs, consisting of 12 hollow globular substructures (HGS). Each HGS is comprised of six dense masses, has a 3-fold symmetry, and is organized in two hexagonally symmetric layers, with the vertices of the upper layer rotated 16 degrees clockwise relative to those of the lower layer. The layers are tethered to a central linker complex, consisting of two bracelets of connections perpendicular to the 6-fold axis and a set of six vertical connections linked to a flat hexagonal mass. HBL[T+L] shared all these features with the native Hb, except for a large hole around the 3-fold symmetry axis in each HGS, indicating the probable location of the missing monomer subunit.

译文

Lu Lu的大约3.5 MDa六角形双层(HBL)血红蛋白(Hb)由单体和球蛋白链以及四种类型的血红素缺陷型连接子链(L)的二硫键结合的三聚体(T)组成。天然Hb和从耗尽单体亚基(HBL [TL])的组成亚基重新组装而成的HBL的低温电子显微镜图像通过随机圆锥倾斜系列方法进行了三维重建。天然血红蛋白的结构与其他无核和有鞭毛的血红蛋白非常相似,由12个空心球状亚结构(HGS)组成。每个HGS由六个密集块组成,具有3倍的对称性,并组织为两个六边形对称的层,上层的顶点相对于下层的顶点顺时针旋转16度。这些层被束缚到中央连接器复合体,该复合体由垂直于6折轴的两个连接腕带和一组连接到平坦六边形质量的六个垂直连接组成。 HBL [TL]与天然Hb具有所有这些特征,除了每个HGS中围绕3折对称轴的一个大洞外,这表明可能缺少单体亚基的位置。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录