Function of new elastic protein

连接蛋白是脊椎动物横纹肌中的一种弹性蛋白。无脊椎动物也具有多种连接蛋白，其中一种是连接蛋白样的4000 kDa蛋白，存在于环节动物的斜横纹肌中。我们已经确定了一个基因的核苷酸序列，该基因编码一种类似于连接蛋白的4000 kDa蛋白，我们发现了一个序列，其中一个47个氨基酸的单位重复了11次。重组蛋白制备完成后，我们进行了超离心分析，并测量了CD谱来估计其二级结构的含量。沉降速度实验表明，该蛋白具有极不对称的形状，整个结构的48%呈β结构。由此证明，这种蛋白质可以覆盖比其他相同大小的普通蛋白质更长的距离。环节动物斜横纹肌的连接蛋白样4000 kDa蛋白具有47个氨基酸重复序列的独特结构，这可能与环节动物斜横纹肌肌节的静息长度约为脊椎动物横纹肌肌节的两倍有关。

Connectin is an elastic protein in vertebrate striated muscle. Invertebrates also possess various connectin-like proteins, one of which is a connectin-like 4000 kDa protein that is present in the obliquely striated muscle of Annelida. We have determined the nucleotide sequence of the gene which encodes a connectin-like 4000 kDa protein in the body wall muscle of Neanthes sp. We discovered a sequence in which a unit of 47 amino acids was repeated 11 times. After preparing the recombinant protein, we performed analytical ultracentrifugation and measured CD spectrum to estimate its secondary structure content. The sedimentation velocity experiment revealed that the protein had an extremely asymmetric shape, and 48% of the whole structure assumed beta-structure. It was thus demonstrated that this protein could cover a longer distance than other ordinary proteins with the same size.The fact that the connectin-like 4000 kDa protein of the obliquely striated muscle of Annelida has a distinct structure with the 47-amino acid repeat sequence may be related to the resting length of a sarcomere in the Annelida obliquely striated muscle, which is about twice as long as that in the vertebrate striated muscle.