Douglas H. Juers
Whitman College
lac operonChemistryBeta-galactosidaseBiochemistryCrystallography
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Publications 63
#1Douglas H. JuersH-Index: 17
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#1Deanna Dahlke Ojennus (Whitworth University)
#2Nicholas J. Bratt (Whitworth University)
Last. Douglas H. Juers (Whitman College)H-Index: 17
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Prolyl aminodipeptidase (PepX) is an enzyme that hydrolyzes peptide bonds from the N-terminus of substrates when the penultimate amino-acid residue is a proline. Prolyl peptidases are of particular interest owing to their ability to hydrolyze food allergens that contain a high percentage of proline residues. PepX from Lactobacillus helveticus was cloned and expressed in Escherichia coli as an N-terminally His-tagged recombinant construct and was crystallized by hanging-drop vapor diffusion in a ...
#1Kaitlin Harrison (Whitman College)
#2Zhenguo Wu (Whitman College)
Last. Douglas H. Juers (Whitman College)H-Index: 17
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Cryocooling for macromolecular crystallography is usually performed via plunging the crystal into a liquid cryogen or placing the crystal in a cold gas stream. These two approaches are compared here for the case of nitro­gen cooling. The results show that gas stream cooling, which typically cools the crystal more slowly, yields lower mosaicity and, in some cases, a stronger anomalous signal relative to rapid plunge cooling. During plunging, moving the crystal slowly through the cold gas layer ab...
#1Douglas H. Juers (Whitman College)H-Index: 17
#2Christopher Farley (Whitman College)H-Index: 2
Last. Z. Wu (Whitman College)
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Cryocooling of macromolecular crystals is commonly employed to limit radiation damage during X-ray diffraction data collection. However, cooling itself affects macromolecular conformation and often damages crystals via poorly understood processes. Here, the effects of cryosolution thermal contraction on macromolecular conformation and crystal order in crystals ranging from 32 to 67% solvent content are systematically investigated. It is found that the solution thermal contraction affects macromo...
#1Marcus A. Juhasz (Whitman College)H-Index: 3
#2Graham R. Matheson (Whitman College)H-Index: 1
Last. Douglas H. Juers (Whitman College)H-Index: 17
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Microwave-assisted syntheses of heavily iodinated 10-vertex and 12-vertex closo boron clusters are reported. Salts of closo-B10I102−, 1-carba-closo-CHB9H4I5−, 1-carba-closo-CB11H6I6−, 1-carba-closo-CHB11I11−, and B12I122− were prepared in yields of 80% or better. All molecules were characterized by NMR and IR spectroscopy and mass spectrometry. The crystal structure of [Et4N][CHB9H4I5] was determined by single crystal X-ray diffraction. This salt crystallizes in the monoclinic P2(1)/c space grou...
6 CitationsSource
#1Jeremy A. Schofield (Whitman College)H-Index: 2
#2William W. Brennessel (UR: University of Rochester)H-Index: 44
Last. Timothy E. Machonkin (Whitman College)H-Index: 13
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Despite the unprecedented selectivity of the hydroquinone ring-cleaving dioxygenase PcpA for ortho-chlorohydroquinones, there are no examples of an ortho-chlorohydroquinone bound to a transition-metal complex. Herein, the synthesis and characterization of (TpPh2Co)2(μ-2,5-dichlorohydroquinonate), for which TpPh2 is tris(3,5-diphenylpyrazolyl)borate, were explored. The dianionic 2,5-dichlorohydroquinonate bridges two (TpPh2Co) moieties and coordinates each cobalt(II) center through the oxygen and...
3 CitationsSource
#1R.W. Wheatley (U of C: University of Calgary)H-Index: 6
#2Douglas H. Juers (Whitman College)H-Index: 17
Last. Sergei Y. Noskov (U of C: University of Calgary)H-Index: 30
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Many enzymes require a specific monovalent cation (M+), that is either Na+ or K+, for optimal activity. While high selectivity M+ sites in transport proteins have been extensively studied, enzyme M+ binding sites generally have lower selectivity and are less characterized. Here we study the M+ binding site of the model enzyme E. coli β-galactosidase, which is about 10 fold selective for Na+ over K+. Combining data from X-ray crystallography and computational models, we find the electrostatic env...
25 CitationsSource
#1David von Stetten (European Synchrotron Radiation Facility)H-Index: 20
#2Thierry Giraud (European Synchrotron Radiation Facility)H-Index: 8
Last. Antoine RoyantH-Index: 18
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The analysis of structural data obtained by X-ray crystallo­graphy benefits from information obtained from complementary techniques, especially as applied to the crystals themselves. As a consequence, optical spectroscopies in structural biology have become instrumental in assessing the relevance and context of many crystallographic results. Since the year 2000, it has been possible to record such data adjacent to, or directly on, the Structural Biology Group beamlines of the ESRF. A core labora...
26 CitationsSource