Open AccessUse of Chromophoric Ligands to Visually Screen Co‐Crystals of Putative Protein‐Nucleic Acid Complexes
Author(s) -
Jiang Xiaohua,
Egli Martin
Publication year - 2011
Publication title -
current protocols in nucleic acid chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.306
H-Index - 17
eISSN - 1934-9289
pISSN - 1934-9270
DOI - 10.1002/0471142700.nc0715s46
Subject(s) - nucleic acid , fluorescence , naked eye , oligonucleotide , chemistry , staining , fluorescence microscope , nucleic acid quantitation , dna , protein crystallization , biochemistry , biology , chromatography , crystallization , organic chemistry , optics , detection limit , physics , genetics
Distinguishing between crystals of protein‐nucleic acid complexes and those containing protein alone is a common problem in structural studies of protein‐nucleic acid interactions. Currently, there are several methods available for detecting nucleic acid in crystals, including gel electrophoresis, SYBR Gold fluorescence dye staining, and methyl violet staining. However, they require either that the crystals be sacrificed or access to a fluorescence microscope. In this protocol, we describe an approach that allows direct visualization of either the presence or absence of oligonucleotides in crystals grown from solutions containing both protein and nucleic acid—labeling with the Cy5 dye. In addition to offering the advantage of being able to distinguish between crystals of complex and protein alone with the naked eye or a light microscope, crystals of covalently Cy5‐labeled DNA can be directly used for X‐ray diffraction data collection. Curr. Protoc. Nucleic Acid Chem . 46:7.15.1‐7.15.8. © 2011 by John Wiley & Sons, Inc.