The Blu-Ice and Distributed Control System (DCS) software packages were developed to provide unified control over the disparate hardware resources available at a macromolecular crystallography beamline. Blu-Ice is a user interface that provides scientific experimenters and beamline support staff with intuitive graphical tools for collecting diffraction data and configuring beamlines for experiments. Blu-Ice communicates with the hardware at a beamline via DCS, an instrument-control and data-acquisition package designed to integrate hardware resources in a highly heterogeneous networked computing environment. Together, Blu-Ice and DCS provide a flexible platform for increasing the ease of use, the level of automation and the remote accessibility of beamlines. Blu-Ice and DCS are currently installed on four Stanford Synchrotron Radiation Laboratory crystallographic beamlines and are being implemented at sister light sources.

Highly fluorinated amino acids have been used to stabilize helical proteins for potential application in various protein-based biotechnologies. To gain further insight into the effect of these highly fluorinated amino acids on helix formation exclusively, we measured the helix propensity of three highly fluorinated amino acids: (S)-5,5,5,5',5',5'-hexafluoroleucine (Hfl), (S)-2-amino-4,4,4-trifluorobutyric acid (Atb), and (S)-pentafluorophenylalanine (Pff). We have developed a short chemoenzymatic synthesis of Hfl with extremely high enantioselectivity (>99%). To measure the helix propensity (w) of the amino acids, alanine-based peptides were synthesized, purified, and investigated by circular dichroism spectroscopy (CD). On the basis of the CD data, the helix propensity of hydrocarbon amino acids can decrease up to 24-fold (1.72 kcal.mol-1.residue-1) upon fluorination. This difference in helix propensity has previously been overlooked in estimating the magnitude of the fluoro-stabilization effect (which has been estimated to be 0.32-0.83 kcal.mol-1.residue-1 for Hfl), resulting in a gross underestimation. Therefore, the full potential of the fluoro-stabilization effect should provide even more stable proteins than the fluoro-stabilized proteins to date.

Highly fluorinated amino acids have been used to stabilize helical proteins for potential application in various protein-based biotechnologies. However, many proteins used for therapeutics and biosensors involve beta-sheet proteins such as antibodies. Accordingly, we explored the effect of several highly fluorinated amino acids on beta-sheet stability including (S)-2-amino-4,4,4-trifluorobutyric acid (Atb), (S)-5,5,5',5'-tetrafluoroleucine (Qfl), (S)-5,5,5,5',5',5'-hexafluoroleucine (Hfl), and (S)-pentafluorophenylalanine (Pff). Nine proteins based on the protein G B1 domain I6A T44A mutant (GB1) with various amino acids at the solvent exposed guest position 53 in the internal strand 4 were synthesized, purified, and investigated by thermal denaturation monitored by circular dichroism spectroscopy. Based on the thermal denaturation data, GB1 stability is affected by the amino acid at the guest position 53. Apparently, introducing fluorine results in more stable GB1 mutants (Pff > Phe, Hfl > Qfl > Leu, Atb > Abu). In particular, GB1 becomes more stable upon introducing fluorines by up to 0.35 kcal x mol(-1) x residue(-1). Overall, these results suggest that fluoro-amino acids may be worthwhile building blocks to explore for stabilizing beta-sheet proteins, which are especially important for biotechnologies such as protein therapeutics and biosensors.