Meshcheryakov Vladimir A, Krieger Inna, Kostyukova Alla S, Samatey Fadel A
Trans-Membrane Trafficking Unit, Okinawa Institute of Science and Technology, Japan.
Acta Crystallogr D Biol Crystallogr. 2011 Sep;67(Pt 9):822-5. doi: 10.1107/S090744491102645X. Epub 2011 Aug 9.
Tropomyosin (TM) is an elongated two-chain protein that binds along actin filaments. Important binding sites are localized in the N-terminus of tropomyosin. The structure of the N-terminus of the long muscle α-TM has been solved by both NMR and X-ray crystallography. Only the NMR structure of the N-terminus of the short nonmuscle α-TM is available. Here, the crystal structure of the N-terminus of the short nonmuscle α-TM (αTm1bZip) at a resolution of 0.98 Å is reported, which was solved from crystals belonging to space group P3(1) with unit-cell parameters a = b = 33.00, c = 52.03 Å, α = β = 90, γ = 120°. The first five N-terminal residues are flexible and residues 6-35 form an α-helical coiled coil. The overall fold and the secondary structure of the crystal structure of αTM1bZip are highly similar to the NMR structure and the atomic coordinates of the corresponding C(α) atoms between the two structures superimpose with a root-mean-square deviation of 0.60 Å. The crystal structure validates the NMR structure, with the positions of the side chains being determined precisely in our structure.
原肌球蛋白（TM）是一种沿着肌动蛋白丝结合的细长双链蛋白。重要的结合位点位于原肌球蛋白的N端。长肌α-TM的N端结构已通过核磁共振（NMR）和X射线晶体学解析。目前仅有短非肌α-TM的N端的NMR结构。在此，报道了短非肌α-TM（αTm1bZip）N端分辨率为0.98 Å的晶体结构，该结构是从属于空间群P3(1)的晶体解析得到的，其晶胞参数为a = b = 33.00，c = 52.03 Å，α = β = 90，γ = 120°。前五个N端残基是灵活的，残基6 - 35形成一个α螺旋卷曲螺旋。αTM1bZip晶体结构的整体折叠和二级结构与NMR结构高度相似，并且两个结构中相应C(α)原子的原子坐标叠加时的均方根偏差为0.60 Å。该晶体结构验证了NMR结构，在我们的结构中侧链位置得到了精确确定。
