It is well established that the majority of energy-converting photosynthetic protein complexes in plant thylakoid membrane are nonhomogenously distributed between stacked and unstacked membrane regions. Yet, the sublocalization of the central cytochrome b₆f complex remains controversial. We present a structural model that explains the variation in cytochrome b₆f sublocalization data. Small changes in the distance between adjacent membranes in stacked grana regions either allow or restrict access of cytochrome b₆f complexes to grana. If the width of the gap falls below a certain threshold, then the steric hindrance prevents cytochrome b₆f access to grana. Evidence is presented that the width of stromal gap is variable, demonstrating that the postulated mechanism can regulate the lateral distribution of the cytochrome b₆f complexes.

众所周知，植物类囊体膜中的大多数能量转换光合作用蛋白复合物均非均匀地分布在堆积和未堆积的膜区域之间。然而，中央细胞色素b ₆ f复合物的亚定位仍存在争议。我们提出了一个结构模型，解释了细胞色素b ₆ f亚定位数据的变化。小在层叠基粒区域允许或限制的细胞色素的访问改变相邻的膜之间的距离b ₆ ˚F络合物基粒。如果间隙的宽度低于某个阈值，则空间位阻会阻止细胞色素b ₆ f访问格兰纳。证据表明，基质间隙的宽度是可变的，表明假定的机制可以调节细胞色素b ₆ f复合物的横向分布。