| Autor: |
Huang Q; MacCHESS, Cornell University , Ithaca, NY 14853, USA., Gruner SM; Department of Physics, Cornell University , Ithaca, NY 14853, USA., Kim CU; MacCHESS, Cornell University, Ithaca, NY 14853, USA; Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, 44919, Republic of Korea., Mao Y; Weill Institute for Cell and Molecular Biology, Cornell University , Ithaca, NY 14853, USA., Wu X; Weill Institute for Cell and Molecular Biology, Cornell University , Ithaca, NY 14853, USA., Szebenyi DM; MacCHESS, Cornell University , Ithaca, NY 14853, USA. |
| Abstrakt: |
High-pressure cryocooling (HPC) has been developed as a technique for reducing the damage that frequently occurs when macromolecular crystals are cryocooled at ambient pressure. Crystals are typically pressurized at around 200 MPa and then cooled to liquid nitrogen temperature under pressure; this process reduces the need for penetrating cryoprotectants, as well as the damage due to cryocooling, but does not improve the diffraction quality of the as-grown crystals. Here it is reported that HPC using a pressure above 300 MPa can reduce lattice disorder, in the form of high mosaicity and/or nonmerohedral twinning, in crystals of three different proteins, namely human glutaminase C, the GTP pyrophosphokinase YjbM and the uncharacterized protein lpg1496. Pressure lower than 250 MPa does not induce this transformation, even with a prolonged pressurization time. These results indicate that HPC at elevated pressures can be a useful tool for improving crystal packing and hence the quality of the diffraction data collected from pressurized crystals. |
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