NMR structure of HMfB from the hyperthermophile, Methanothermus fervidus, confirms that this archaeal protein is a histone.
NMR structure of HMfB from the hyperthermophile, Methanothermus fervidus, confirms that this archaeal protein is a histone.
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来自超嗜热菌 Methanothermus fervidus 的 HMfB 的 NMR 结构证实了这种古菌蛋白是一种组蛋白。
DOI：
10.1006/jmbi.1996.0016
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Summers,MF
中科院分区：
文献类型：
--
作者：
Starich,MR;Sandman,K;Reeve,JN;Summers,MF
用核磁共振方法测定了在83℃条件下生长最适的古细菌--费氏甲烷热杆菌重组组蛋白rHMfB的三维结构。这只是高温有机体中蛋白质的第三种结构(温度在80°C以上时生长的最佳温度)。结合同核相关、15N-双共振和15N、13C三重共振的核磁共振实验进行了信号归属。从二维13C双半过滤和三维13C过滤的核磁共振数据中鉴定了对称性同二聚体的长程偶极相互作用。用DSPACETM计算了一个由33个结构组成的家族，共609个NOE衍生的质子间距离限制，包括22个残基内，192个序列，300个中程(2~5个残基)，86个长程分子内(5个以上残基)和112个分子间距离限制。单体亚基由三个α-螺旋组成，从Pro4残基延伸到Ala15(螺旋I)，Ser21延伸到Ala50(螺旋II)，Lys56延伸到Lys68(螺旋III)，以及两个短的β链片段，由残基Arg19到Ser21和Thr54到Ile55组成。螺旋I、II和III包含N-末端帽盒，螺旋I和II包含C-末端帽。(RHMfB)2二聚体的结构与鸡核小体的组蛋白核心八聚体中的二聚体亚基非常相似。RHMfB中典型的组蛋白折叠基序的存在与古生物组蛋白HMF家族和从共同祖先进化而来的真核小体核心组蛋白一致。(RHMfB)2二聚体包含几个可能赋予热稳定性(或非稳定性)的结构特征，包括两个新的疏水“Pro-line NCAP”，四个螺旋间氢键和短的N-端和C-端无序尾巴。
The three-dimensional structure of the recombinant histone rHMfB fromMethanothermus fervidus, an archaeon that grows optimally at 83°C, has been determined by nuclear magnetic resonance methods. This is only the third structure of a protein from a hyperthermophilic organism (optimal growth at temperatures above 80°C). Signal assignments were made using a combination of homonuclear-correlated,15N-double resonance and15N,13C triple resonance NMR experiments. Long range dipolar interactions for the symmetric homodimer were identified from two-dimensional13C- double half-filtered and three-dimensional13C-filtered NMR data obtained for a heterolabeled-dimer. A family of 33 structures was calculated using DSPACETMwith a total of 609 NOE-derived interproton distance restraints, including 22 intraresidue, 192 sequential, 300 medium-range (two to five residues), 86 long-range intramolecular (more than five residues) and 112 intermolecular distance restraints. The monomer subunits consist of three α-helices, extending from residues Pro4 to Ala15 (helix I), Ser21 to Ala50 (helix II) and Lys56 to Lys68 (helix III), as well as two short segments of β-strand comprised of residues Arg19 to Ser21 and Thr54 to Ile55. Helices I, II and III contain N-terminal capping boxes, and helices I and II contain C-terminal caps. The structure of the (rHMfB)2dimer appears very similar to the dimer subunits within the histone core octamer of the chicken nucleosome. The presence of a canonical “histone fold” motif in rHMfB is consistent with the HMf family of archaeal histones and the eukaryal nucleosome core histones having evolved from a common ancestor. The (rHMfB)2dimer contains several structural features that may impart thermal stability (or non-lability), including two novel hydrophobic “proline Ncaps”, four interhelical hydrogen bonds and short N- and C-terminal disordered tails.