A new Differential Scanning Calorimeter for the multi-user Molecular Biophysics Research Centre

差示扫描量热法（DSC）是一种重要的生物物理技术，可用于确定蛋白质的稳定性或脂质层的稳定性作为温度的函数。通过逐渐增加特定“温控”隔室中的温度，可以获得蛋白质变性温度的准确估计。当配体与蛋白质结合时，蛋白质的变性温度（即蛋白质失去其3D结构的温度）通常会增加。这种增加的程度与相互作用的强度直接相关。所有市售的DSC仪器都可以自动进行这些测量。因此，DSC已成为比较各种配体（如酶底物、辅因子或辅酶、药物、药物先导物、金属离子或调节化合物）与纯化蛋白质结合的重要方法。在制药工业中，DSC被广泛用于研究蛋白质治疗剂的稳定性和筛选最佳制剂条件。DSC的主要优点是它是一种完全无标记的测量：测量的参数是蛋白质展开和重折叠时吸收（或产生）的热量。 脂质相变也可以通过DSC测量直接跟踪。近年来，许多工作集中在磷脂的研究，生物膜的主要成分。不同的磷脂双层和多层在其相行为中具有特征性转变，其发生在特定温度下，这取决于其脂肪酸链的长度和其磷脂头基的化学性质。当跨膜蛋白或干扰剂，如抗微生物或抗癌肽，与这些膜模拟物结合时，相行为发生变化，通常会产生被选定脂质包围的不同肽片，然后显示不同的转变温度。因此，在这种情况下，无标记DSC测量有助于表征脂质与生物膜的其他组分之间的相互作用。 为什么我们现在申请DSC仪器？2001年，我们有幸购买了第一台Microcal VP-DSC仪器。该仪器一直在继续使用，多年来为我们提供了很好的服务;所获得的结果已被列入许多出版的手稿。该仪器被纳入多用户生物物理学研究中心，该中心拥有来自我们校园的所有用户。原来的DSC仪器最近发生了泄漏，制造商给我们报了一个很高的价格来修理仪器。考虑到仪器的年龄（其中包括一个过时的过时的计算机系统），维修费用似乎过高。因此，我们决定，现在是时候用一种新的设备来取代它，为我们提供未来15年的可靠数据。

Differential Scanning Calorimetry (DSC) is an important biophysical technique that can be used to determine the stability of proteins or the stability of lipid layers as a function of temperature. By gradually increasing the temperature in a specific ‘thermo-controlled’ compartment one can obtain an accurate estimate of the denaturation temperature of a protein. The denaturation temperature of the protein - the point where it looses its 3D structure - typically increases when ligands bind to the protein. The extent of this increase is directly related to the strength of the interaction. All commercially available DSC instruments can carry out these measurements in an automated fashion. Hence DSC has become an important method to compare the binding of various ligands, such as enzyme substrates, co-factors or co-enzymes, drugs, drug leads, metal ions or regulatory compounds to purified proteins. In the pharmaceutical industry DSC is being used extensively to study the stability of protein therapeutics and to screen for optimal formulation conditions. The main advantage of DSC is that it is a completely label-free measurement: the parameter measured is the heat that is absorbed (or produced) when proteins unfold and refold. Lipid phase transitions can also be followed directly by DSC measurements. In recent years much work has focused on studies of phospholipids, the major constituents of biological membranes. Distinct phospholipid bilayers and multilayers have characteristic transitions in their phase behaviour that occur at specific temperatures depending on the length of their fatty acid chains and the chemical nature of their phospholipid headgroups. When transmembrane proteins or perturbing agents, such as antimicrobial or anticancer peptides, are binding to these membrane mimetics, the phase behavior changes, often creating distinct patches of peptides that are surrounded by selected lipids, which then display different transition temperatures. Hence in this case the label-free DSC measurements help to characterize the interplay between the lipids and the other components of biological membranes. Why do we apply now for a DSC instrument? In 2001 we were fortunate that we could purchase our first Microcal VP-DSC instrument. The instrument has been in continued use and it has served us well over the years; the results obtained have been included in numerous published manuscripts. The instrument is incorporated in the multiuser Biophysics Research Centre, which has users from all across our campus. The original DSC instrument has recently developed a leak and the manufacturer has quoted us a steep price to have the instrument repaired. Given the age of the instrument (which includes an outdated obsolete computer system) the repair cost seems exorbitant. We have therefore decided that the time has come to replace it with a new device that can provide us with reliable data for the next 15 years.