Mass spectrometry guided in situ proteolysis to obtain crystals for X-ray structure determination.
A strategy for increasing the efficiency of protein crystallization/structure determination with mass spectrometry has been developed. This approach combines insights from limited proteolysis/mass spectrometry and crystallization via in situ proteolysis. The procedure seeks to identify protease-resistant polypeptide chain segments from purified proteins on the time-scale of crystal formation, and subsequently crystallizing the target protein in the presence of the optimal protease at the right relative concentration. We report our experience with 10 proteins of unknown structure, two of which yielded high-resolution X-ray structures. The advantage of this approach comes from its ability to select only those structure determination candidates that are likely to benefit from application of in situ proteolysis, using conditions most likely to result in formation of a stable proteolytic digestion product suitable for crystallization.
Gheyi
Tarun
T
New York SGX Research Center for Structural Genomics, Structural Biology, Eli Lilly and Company, Lilly Biotechnology Center, San Diego, California 92121, USA. Gheyi_Tarun@lilly.com
Rodgers
Logan
L
Romero
Richard
R
Sauder
J Michael
JM
Burley
Stephen K
SK
D003460:Crystallization / Q000379:methods; D018360:Crystallography, X-Ray; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods*; D010446:Peptide Fragments / Q000737:chemistry; D010447:Peptide Hydrolases / Q000378:metabolism; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry / Q000378:metabolism
D029968:Escherichia coli Proteins; D010446:Peptide Fragments; D011506:Proteins; D010447:Peptide Hydrolases