A novel class of secreted hydrophobic proteins is involved in aerial hyphae formation in Streptomyces coelicolor by forming amyloid-like fibrils
A novel class of secreted hydrophobic proteins is involved in aerial hyphae formation in Streptomyces coelicolor by forming amyloid-like fibrils
复制标题
DOI：
10.1101/gad.264303
复制
发表时间：
2003-07-15
影响因子：
10.5
通讯作者：
Wösten, HAB
中科院分区：
文献类型：
--
作者：
Claessen, D;Rink, R;Wösten, HAB
链霉菌表现出复杂的形态分化。在沉水的菌丝体形成后，丝状物生长到空气中以分离成孢子。一类8种疏水分泌蛋白CHPA-H被证明在天蓝色链霉菌的发育过程中起着重要作用。成熟形式的ChpD-H长达63个氨基酸，而CHPA-C更大(+/-225个氨基酸)。CHPA-C含有与ChpD-H相似的两个结构域，以及一个细胞壁分选信号。CHP基因在沉水菌丝体(chpE和chpH)和气生菌丝(CHPA-H)中均有表达。其中6个CHP基因缺失的菌株(DeltachpABCDEH)对气生菌丝的形成有强烈的影响。从气生菌丝细胞壁纯化的ChpD-H混合物在胞外补充DeltachpABCDEH菌株，并促进野生型菌株的发育。这种蛋白质混合物具有高度的表面活性，它在水-空气界面上自组装成类淀粉样纤维。这些原纤维类似于气生菌丝的表层。因此，我们得出结论，ChpD-H的淀粉样纤维降低了水表面张力，从而允许气生生长并覆盖气生结构，使它们疏水性。CHPA-C可能与ChpD-H结合在细胞壁上。
Streptomycetes exhibit a complex morphological differentiation. After a submerged mycelium has been formed, filaments grow into the air to septate into spores. A class of eight hydrophobic secreted proteins, ChpA-H, was shown to be instrumental in the development of Streptomyces coelicolor. Mature forms of ChpD-H are up to 63 amino acids in length, and those of ChpA-C are larger (+/-225 amino acids). ChpA-C contain two domains similar to ChpD-H, as well as a cell-wall sorting signal. The chp genes were expressed in submerged mycelium (chpE and chpH) as well as in aerial hyphae (chpA-H). Formation of aerial hyphae was strongly affected in a strain in which six chp genes were deleted (DeltachpABCDEH). A mixture of ChpD-H purified from cell walls of aerial hyphae complemented the DeltachpABCDEH strain extracellularly, and it accelerated development in the wild-type strain. The protein mixture was highly surface active, and it self-assembled into amyloid-like fibrils at the water-air interface. The fibrils resembled those of a surface layer of aerial hyphae. We thus conclude that the amyloid-like fibrils of ChpD-H lower the water surface tension to allow aerial growth and cover aerial structures, rendering them hydrophobic. ChpA-C possibly bind ChpD-H to the cell wall.