Nucleotide-induced conformational changes of tetradecameric GroEL mapped by H/D exchange monitored by FT-ICR mass spectrometry

作者：Zhang Qian; Chen Jin; Kuwajima Kunihiro; Zhang Hui Min; Xian Feng; Young Nicolas L; Marshall Alan G^*

来源：Scientific Reports, 2013, 3: 1247.

DOI：10.1038/srep01247

Here we employ hydrogen/deuterium exchange mass spectrometry (HDX-MS) to access E. coli chaperonin GroEL conformation. The similar to 800 kDa tetradecameric GroEL plays an essential role in the proper folding of many proteins. Previous studies of the structural dynamics of GroEL upon ATP binding have been inconsistent, showing either minimal or major allosteric changes. Our results, based on the native, non-mutated, protein under physiological conditions in solution demonstrate substantial changes in conformation and/or flexibility upon ATP binding. We capture the pivotal step in its functional cycle by use of a non-hydrolyzable ATP analog, ATP gamma S, to mimic the ATP-bound GroEL state. Comparison of HDX-MS results for apo GroEL and GroEL-ATP gamma S enables the characterization of the nucleotide-regulated conformational changes throughout the entire protein with high sequence resolution. The 14-mer GroEL complex is the largest protein assembly yet accessed by HDX-MS, with sequence resolution of segments of as few as five amino acids.

• 出版日期2013-2-13