J. Chrzas

Argonne National Laboratory, Лимонт, Illinois, United States

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Publications (13)29.59 Total impact

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    ABSTRACT: For the past 15 years, SER-CAT has been striving to provide its members with access to a "virtual beamline" which could be integrated into their daily workflow much like the X-ray lab down the hall. Working with Oceaneering Space Systems a conceptual design for automated data collection robot (ASTRO) was developed in 2000. In 2003, using funds from the Georgia Research Alliance, automation of the SER-CAT beamlines began with the installation of a highly modified Berkeley/ALS automounter (6 pucks) on beamline 22BM followed by a higher capacity system (15 pucks) installed on 22ID. SER-CAT automation also includes seamless integration with the SERGUI beamline control system, SER-CAT/UGA production of the tools (pucks, etc.) users need to ship crystals to the beamline and automated crystal screening and data reduction systems. Today over 95% of SER-CAT members routinely collect data remotely. Efficient and reliable automation has also allowed SER-CAT to offer two 12-hour data collection shifts per day with extended 16-hour/day on-site user support. An overview of SER-CAT beamline automation including robotics, beamline/experiment control, and automated data processing and structure determination will be described. Work supported by NIH NCRR (S10RR025528 & S10RR028976), SER-CAT Member Institutions, University of Georgia Research Foundation and the Georgia Research Alliance.
    No preview · Article · Aug 2014 · Acta Crystallographica Section A: Foundations and Advances
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    ABSTRACT: Investigating Data Collection Strategies for the Rayonix MX300HS 10 Hz CCD Detector Zhongmin Jin, John Chrzas, James Fait, Zheng-Qing Fu, Rod Salazar, John Gonczy, Unmesh Chinte, Palani Kandavelu, John P. Rose and Bi-Cheng Wang SERCAT, APS, Argonne National Lab, Argonne, IL 60439 and Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA. Earlier this year SER-CAT received its Rayonix MX300HS high-speed area detector purchased with funds awarded from an NIH grant. The detector is CCD based (4X4 taper/chip array) with a 1-2 millisecond readout speed and 8e-/pixel (78 micron/pixel) readout noise providing 10Hz data collection capabilities. In its slower readout mode, the readout noise can be further reduced to about 4e-/pixel, which is less than 1 ADU. The detector was installed in late January on beamline 22BM for integration with SER-CAT's beamline control system and commissioning. This detector is the first of its kind and its fast readout time will allow us to collect data in the traditional shuttered mode with both normal and low noise readout; or in shutter-less mode using 0.1 second exposures with constant rotation of crystal. Importantly, the shutter-less mode may enhance system precision and improve the quality of the resulting data since it should eliminate mechanical errors associated with shutter jitter, shutter synchronization and goniometer backlash during data collection. Based on our preliminary tests, shutter-less mode data collection has confirmed the expectation of being capable for providing better quality data than that from shuttered mode. Shutter-less data collection also offers the ability to efficiently collect fine slice data, which will further improve the signal to noise in the data. We will present the results from systematic tests of the detector in terms of frame width (rotation angle per frame), rotation speed, exposure time, dynamic range etc. Work supported in part by NIH NCRR (S10RR028976), SER-CAT, The University of Georgia and the Advanced Photon Source.
    No preview · Article · Aug 2014 · Acta Crystallographica Section A: Foundations and Advances
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    ABSTRACT: The crystal structure of the 11.14 kDa orphan ORF 1382 from Archaeoglobus fulgidus (AF1382) has been determined by sulfur SAD phasing using a moderately diffracting crystal and 1.9 Å wavelength synchrotron X-rays. AF1382 was selected as a structural genomics target by the Southeast Collaboratory for Structural Genomics (SECSG) since sequence analyses showed that it did not belong to the Pfam-A database and thus could represent a novel fold. The structure was determined by exploiting longer wavelength X-rays and data redundancy to increase the anomalous signal in the data. AF1382 is a 95-residue protein containing five S atoms associated with four methionine residues and a single cysteine residue that yields a calculated Bijvoet ratio (ΔF(anom)/F) of 1.39% for 1.9 Å wavelength X-rays. Coupled with an average Bijvoet redundancy of 25 (two 360° data sets), this produced an excellent electron-density map that allowed 69 of the 95 residues to be automatically fitted. The S-SAD model was then manually completed and refined (R = 23.2%, R(free) = 26.8%) to 2.3 Å resolution (PDB entry 3o3k). High-resolution data were subsequently collected from a better diffracting crystal using 0.97 Å wavelength synchrotron X-rays and the S-SAD model was refined (R = 17.9%, R(free) = 21.4%) to 1.85 Å resolution (PDB entry 3ov8). AF1382 has a winged-helix-turn-helix structure common to many DNA-binding proteins and most closely resembles the N-terminal domain (residues 1-82) of the Rio2 kinase from A. fulgidus, which has been shown to bind DNA, and a number of MarR-family transcriptional regulators, suggesting a similar DNA-binding function for AF1382. The analysis also points out the advantage gained from carrying out data reduction and structure determination on-site while the crystal is still available for further data collection.
    Full-text · Article · Sep 2012 · Acta Crystallographica Section D Biological Crystallography
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    B.-C. Wang · Z. Fu · J. Fait · A. Howard · J. Chrzas · L. Chen · J. Rose

    Full-text · Article · Aug 2008 · Acta Crystallographica Section A Foundations of Crystallography
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    Z.-Q. Fu · J. Chrzas · J. Fait · Z. Jin · A. Howard · J. Gonczy · J.P. Rose · B.-C. Wang

    Full-text · Article · Aug 2008 · Acta Crystallographica Section A Foundations of Crystallography
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    Full-text · Article · Aug 2008 · Acta Crystallographica Section A Foundations of Crystallography
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    ABSTRACT: Familial oncocytic thyroid carcinoma is associated with a missense mutation, P308Q, in the C-terminal domain of Tim44. Tim44 is the mitochondrial inner-membrane translocase subunit and it functions as a membrane anchor for the mitochondrial heat-shock protein 70 (mtHsp70). Here, the crystal structure of the human Tim44 C-terminal domain complexed with pentaethylene glycol has been determined at 1.9 A resolution. The overall structure resembles that of the nuclear transport factor 2-like domain. In the crystal structure, pentaethylene glycol molecules are associated at two potential membrane-binding sites: the large hydrophobic cavity and the highly conserved loop between the alpha1 and alpha2 helices near Pro308. A comparison with the yeast homolog revealed that lipid binding induces conformational changes around the alpha1-alpha2 loop, leading to slippage of the alpha1 helix along the large beta-sheet. These changes may play important roles in the translocation of polypeptides across the mitochondrial inner membrane.
    Full-text · Article · Jan 2008 · Acta Crystallographica Section D Biological Crystallography
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    ABSTRACT: A parallel algorithm has been designed for SHELXD to solve the heavy-atom partial structures of protein crystals quickly. Based on this algorithm, a program has been developed to run on high-performance multiple-CPU Linux PCs, workstations or clusters. Tests on the 32-CPU Linux cluster at SER-CAT, APS, Argonne National Laboratory, show that the parallelization dramatically speeds up the process by a factor of roughly the number of CPUs applied, leading to reliable and instant heavy-atom sites solution, which provides the practical opportunity to employ heavy-atom search as an alternative tool for anomalous scattering data quality evaluation during single/multiple-wavelength anomalous diffraction (SAD/MAD) data collection at synchrotron beamlines.
    No preview · Article · Apr 2007 · Journal of Applied Crystallography
  • Z. Q. Fu · J. Chrzas · G. Sheldrick · J.P. Rose · B.C. Wang

    No preview · Article · Jan 2007

  • No preview · Article · Aug 2005 · Acta Crystallographica Section A Foundations of Crystallography

  • No preview · Article · Aug 2002 · Acta Crystallographica Section A Foundations of Crystallography
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    ABSTRACT: MurF is required to catalyze the final step in the synthesis of the cytoplasmic precursor of the bacterial cell wall peptidoglycan, rendering it an attractive target for antibacterial drug development. The crystal structure of the MurF apo-enzyme has been determined using the multiwavelength anomalous dispersion method and refined to 2.3 A resolution. It contains three consecutive open alpha/beta-sheet domains. In comparison with the complex crystal structures of MurD and its substrates, The topology of the N-terminal domain of MurF is unique, while its central and C-terminal domains exhibit similar mononucleotide and dinucleotide-binding folds, respectively. The apo-enzyme of MurF crystal structure reveals an open conformation with the three domains juxtaposed in a crescent-like arrangement creating a wide-open space where substrates are expected to bind. As such, catalysis is not feasible and significant domain closure is expected upon substrate binding.
    Preview · Article · Jan 2001 · Journal of Molecular Biology
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    ABSTRACT: A simple and robust design for the liquid nitrogen-cooled first monochromator crystal suitable for large Bragg-angles has been implemented at three undulator beamlines at the Advanced Photon Source (IMCA CAT, BioCAT, and MR CAT). The design features a simple and reliable seal and a strain free mount. The system has been pressure tested intentionally and accidentally to failure and the crystal reseals. Measurements have been made under closed gap conditions with little indication of distortion. The crystal design, implementation and measurements are presented
    No preview · Article · Jan 2000 · AIP Conference Proceedings