A molecular understanding of how stable single alpha helical domains behave as constant force springs in proteins.

从分子角度理解稳定的单 α 螺旋结构域如何充当蛋白质中的恒力弹簧。

• 批准号: BB/M009114/1
• 负责人: Michelle Peckham
• 金额: $ 51.6万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FM009114%2F1
• 关键词: molecular; understanding; how; stable; single

Proteins in cells are commonly exposed to forces. We have recently discovered a specialised protein domain that helps to separate different domains in a single protein, and we now think that it also protects them from unfolding when they are exposed to forces within the cell. This novel domain is a special type of alpha helix, one of the two main types of protein fold. Unlike other alpha helices, this type is highly stable by itself and its bending stiffness is reasonably high, which means it can act as a 'spacer'; when sandwiched between two domains in a protein, rather like a fairly flexible rod between two balls, in a weightlifting barbell. It separates those domains by a defined amount that simply depends on its length, as each residue is separated by 0.15nm in an alpha helix, and thus, the higher the number of residues, the longer spacer. We call this type of helix a 'SAH' domain (for stable single alpha helix). Our latest data on this SAH domain suggest that while its bending stiffness is reasonably high, if it is pulled on (experiences forces) along its length, then it progressively unravels, and as it does so, it maintains force at a constant level. This is rather different to a spring, where the force would continue to rise as the ends of the spring are pulled apart. If the SAH domain acted as a spring, there would be a danger that the adjacent protein domains would also unfold if the force rose to a high enough level, damaging their function. In contrast, by maintaining a constant force, while the SAH is unfolding and elongating, the adjacent protein domains are protected from unfolding, and from detaching from the protein complex that they interact with, when they are exposed to forces. What we now plan to do is to determine exactly what level of forces the SAH domain unfolds under, if it is exposed to this level of forces in a cell, and if so, if those forces really do unfold the SAH domain and make it unfold, as we suspect. We also want to determine the structure of the SAH domain, to understand how the charged amino acids in a typical SAH domain sequence interact, so we can understand at a molecular level, how the amino acids interact and enable this special type of alpha helix to be so stable. This new work will give us unprecedented insight into the structure and function of the SAH domain, enabling us to exploit its properties in artificial proteins in the future.

细胞中的蛋白质通常受到外力的作用。我们最近发现了一种特殊的蛋白质结构域，它有助于在单个蛋白质中分离不同的结构域，我们现在认为，当它们暴露在细胞内的力时，它也可以保护它们不展开。这种新的结构域是一种特殊类型的α螺旋，是蛋白质折叠的两种主要类型之一。与其他α螺旋不同，这种类型本身非常稳定，其弯曲刚度相当高，这意味着它可以作为“间隔”；当夹在蛋白质的两个结构域之间时，就像举重杠铃中两个球之间的一根相当柔韧的杆。它将这些结构域分开的数量取决于它的长度，因为每个残基在α螺旋中间隔0.15nm，因此，残基数量越多，间隔越长。我们称这种类型的螺旋为“SAH”结构域（稳定的单α螺旋）。我们关于这个SAH域的最新数据表明，虽然它的弯曲刚度相当高，但如果它沿着它的长度被拉（经历力），那么它会逐渐解开，并且当它这样做时，它将力保持在恒定的水平。这与弹簧非常不同，弹簧的两端被拉开时，力会继续上升。如果SAH结构域像弹簧一样起作用，那么如果力上升到足够高的水平，邻近的蛋白质结构域也会展开，从而破坏它们的功能，这将是一种危险。相反，通过保持恒定的力，当SAH展开和伸长时，当它们暴露于力时，相邻的蛋白质结构域被保护不展开，也不脱离与它们相互作用的蛋白质复合物。我们现在计划做的是确定SAH结构域在多大程度的力下展开，如果它在细胞中暴露在这种水平的力下，如果是这样，如果这些力真的展开了SAH结构域并使它展开，正如我们所猜测的那样。我们还想确定SAH结构域的结构，了解典型SAH结构域序列中的带电氨基酸是如何相互作用的，这样我们就能在分子水平上理解，氨基酸是如何相互作用的并使这种特殊类型的α螺旋如此稳定。这项新工作将使我们对SAH结构域的结构和功能有前所未有的了解，使我们能够在未来利用其在人工蛋白质中的特性。

项目成果

Determining Stable Single Alpha Helical (SAH) Domain Properties by Circular Dichroism and Atomic Force Microscopy.

通过圆二色性和原子力显微镜确定稳定的单 α 螺旋 (SAH) 域特性。

• DOI: 10.1007/978-1-4939-8556-2_10
• 发表时间: 2018
• 期刊: Methods in molecular biology (Clifton, N.J.)
• 作者: Batchelor M

Nonexponential Kinetics of Loop Formation in Proteins and Peptides: A Signature of Rugged Free Energy Landscapes?

• DOI: 10.1021/acs.jpcb.7b07075
• 发表时间: 2017-10-19
• 期刊: JOURNAL OF PHYSICAL CHEMISTRY B
• 影响因子: 3.3
• 作者: Gowdy, James;Batchelor, Matthew;Paci, Emanuele
• 通讯作者: Paci, Emanuele

Differential Effects of Hydrophobic Core Packing Residues for Thermodynamic and Mechanical Stability of a Hyperthermophilic Protein

• DOI: 10.1021/acs.langmuir.6b01550
• 发表时间: 2016-07-26
• 期刊: LANGMUIR
• 影响因子: 3.9
• 作者: Tych, Katarzyna M.;Batchelor, Matthew;Dougan, Lorna
• 通讯作者: Dougan, Lorna

Tuning protein mechanics through an ionic cluster graft from an extremophilic protein.

通过从极端蛋白质中移植离子簇来调整蛋白质力学。

• DOI: 10.1039/c5sm02938d
• 发表时间: 2016
• 期刊: Soft matter
• 影响因子: 3.4
• 作者: Tych KM