MembFac is based upon the highly effective biased sparse matrix methodology. The MembFac screen matrix is optimized for the crystallization of membrane proteins.

MembFac contains 48 unique reagent formulations. With this set of 48 conditions, numerous chemicals and chemical combinations are utilized, allowing one to evaluate a large variety of potential crystallization conditions. MembFac covers a broad pH range between 4 and 9.

The Rationale The basic rationale of MembFac is to perform a sparse matrix screen while changing the detergent dimension because detergents play an important factor in the crystallization of membrane proteins. A MembFac screen is to be completed for each detergent. Detergent screens are available separately.

The Method The membrane protein of interest is first isolated in the detergent which gives the highest stability and activity. The protein concentration should be approximately 10 to 20 mg/ml and the detergent concentration should be only slightly above the CMC. The sample is then set against MembFac, using all 48 solutions plus the screening detergent(s) of choice. The screening detergent concentration should be approximately one to three times the CMC. Hence, for each detergent screened, one would utilize approximately 1 to 2 mg of sample.

The MembFac protocol was used to crystallize membrane proteins including SQR, fumerate: quinone oxireductase, LHII, and LHCII.

Crystal Screen Lite is a sparse matrix of trial crystallization reagent conditions based upon the Crystal Screen™.³ The primary screen variables are salt, pH, and precipitant (salts, polymers, volatile organics, and non-volatile organics).² Crystal Screen Lite differs from the original Crystal Screen kit in that the primary precipitant reagents are one-half the concentration of that used in the original Crystal Screen formulation. The secondary salts, ions, and buffers remain at the original Crystal Screen concentration. Reducing the primary concentration of the primary precipitant results in a screen which is “more gentle” on the sample and typically produces much less precipitate conditions than the original Crystal Screen.

MembFac contains 48 unique reagents, 10 ml each.

MembFac HT contains 1 ml each of all 48 reagents from MembFac and reagents 1-48 from Crystal Screen Lite in a single Deep Well block format.

Ready-to-use reagents are sterile filtered and formulated with ultra-pure Type 1 water, using the highest purity salts, polymers, organics and buffers. Individual reagents are available through the Hampton Research Custom Shop.

应用
膜蛋白和溶解度有限的样品的初级稀疏基质结晶筛选
特征
膜蛋白稀疏矩阵筛选
稀疏矩阵公式可有效地对盐、聚合物、有机物和 pH 值进行采样
pH 范围 4.6 – 8.5
与洗涤剂一起使用
管或深井块格式
Crystal Screen Lite 的离子强度低于原始 Crystal Screen
描述
MembFac 是一种高效的稀疏矩阵筛选，专门设计用作膜蛋白结晶的初步筛选。MembFac 基于高效的有偏稀疏矩阵方法。 MembFac 筛选矩阵针对膜蛋白的结晶进行了优化。

MembFac 包含 48 种独特的试剂配方。通过这组 48 种条件，可以使用多种化学品和化学组合，从而可以评估多种潜在的结晶条件。 MembFac 涵盖了 4 到 9 之间的广泛 pH 范围。

基本原理 MembFac 的基本原理是在改变去污剂维度的同时进行稀疏矩阵筛选，因为去污剂在膜蛋白的结晶中起着重要的作用。每种洗涤剂都要完成一个 MembFac 筛选。清洁剂筛网可单独购买。

方法 首先在具有最高稳定性和活性的去污剂中分离目标膜蛋白。蛋白质浓度应约为 10 至 20 毫克/毫升，洗涤剂浓度应仅略高于 CMC。然后使用所有 48 种溶液加上所选的筛选去污剂，将样品与 MembFac 进行对比。筛选洗涤剂浓度应约为 CMC 的一到三倍。因此，对于筛选的每种洗涤剂，将使用大约 1 至 2 毫克的样品。

MembFac 方案用于结晶膜蛋白，包括 SQR、延胡索酸：醌氧化还原酶、LHII 和 LHCII。

Crystal Screen Lite 是基于 Crystal Screen™ 的试验结晶试剂条件的稀疏矩阵。3 主要筛选变量是盐、pH 和沉淀剂（盐、聚合物、挥发性有机物和非挥发性有机物）。2 Crystal Screen Lite与原始 Crystal Screen 试剂盒的不同之处在于，主要沉淀剂的浓度是原始 Crystal Screen 配方中使用的浓度的一半。二级盐、离子和缓冲液保持原始 Crystal Screen 浓度。降低主要沉淀剂的主要浓度会导致筛网对样品“更温和”，并且通常比原始晶体筛网产生的沉淀条件少得多。

MembFac 包含 48 种独特的试剂，每种 10 ml。

MembFac HT 在单个深孔模块中包含来自 MembFac 的所有 48 种试剂和来自 Crystal Screen Lite 的试剂 1-48 各 1 ml。

即用型试剂经过无菌过滤和超纯 1 类水配制，使用最高纯度的盐、聚合物、有机物和缓冲液。个别试剂可通过 Hampton Research Custom Shop 购买。

 

MembFac

Crystal Screen Lite

MembFac HT

 HR2-114 MembFac Documents HR2-114 MembFac SDS HR2-128 Crystal Screen Lite Documents HR2-128 Crystal Screen Lite SDS HR2-137 MembFac HT Documents HR2-137 MembFac HT SDS MembFac & Crystal Screen Lite Formulation & Scoring Data

1. UCLA Crystallization Workshop, June 21, 1993.

2. Crystallization of nucleic acids and proteins, Edited by A. Ducruix and R. Giege, The Practical Approach Series, Oxford Univ. Press, 1992.

3. McPherson, A., Current approaches to macromolecular crystallization., Eur. J. Biochem. (1990) 189, 1-23.

4. Jancarik, J. and Kim, S.H., Sparse Matrix Sampling: a screening method for crystallization of proteins. (1991) J. Appl. Cryst., 24,409-411.

5. Protein and Nucleic Acid Crystallization. Methods, A Companion to Methods in Enzymology, Academic Press, Volume 1, Number 1, August 1990.

6. Structural and functional characterization of the N-terminal domain of the yeast Mg2+ channel Mrs2. M. B. Khan, G. Sponder, B. Sjoblom, S. Svidova, R. J. Schweyen, O. Carugo and K. Djinovic-Carugo. Acta Cryst. (2013). D69, 1653-1664.