June 2026 - phenixbb - phenix-online.org

Question about geometry outliers in RealSpaceRefine
by Kevin M Jude 06 Jun '26

06 Jun '26

After a recent RealSpaceRefine run, the Geometry Restraints tab in the gui reports that I have two bond angle outliers > 4 sigma, but only lists one of them: D 180 MET N, D 180 MET CA, D 180 MET CB 114.170 109.342 4.2 So I check the logfile for the job and see: Bond angle restraints: 12582 Sorted by residual: angle pdb=" N MET D 180 " pdb=" CA MET D 180 " pdb=" CB MET D 180 " ideal model delta sigma weight residual 114.17 109.34 4.83 1.14e+00 7.69e-01 1.79e+01 angle pdb=" CA LEU B 79 " pdb=" CB LEU B 79 " pdb=" CG LEU B 79 " ideal model delta sigma weight residual 116.30 127.81 -11.51 3.50e+00 8.16e-02 1.08e+01 angle pdb=" C ASP B 333 " pdb=" N SER B 334 " pdb=" CA SER B 334 " ideal model delta sigma weight residual 122.74 127.19 -4.45 1.44e+00 4.82e-01 9.54e+00 angle pdb=" C GLN D 167 " pdb=" N ARG D 168 " pdb=" CA ARG D 168 " ideal model delta sigma weight residual 121.48 126.80 -5.32 2.04e+00 2.40e-01 6.80e+00 angle pdb=" C ASP B 163 " pdb=" N THR B 164 " pdb=" CA THR B 164 " ideal model delta sigma weight residual 123.47 127.30 -3.83 1.53e+00 4.27e-01 6.27e+00 ValidationCryoEM returns identical results except the gui says only one > 4-sigma outlier (at //D/Met180/). PDB Validation reports only the outlier at //B/Leu79/, which does have the largest sigma in the above log. My questions are: 1. Why does the gui report two 4-sigma outliers but only show one? 2. Why do the sigmas in the log file not correspond to the sigmas in the gui? Best wishes Kevin -- Kevin Jude, PhD Structural Biology Research Specialist, Garcia Lab Howard Hughes Medical Institute Stanford University School of Medicine Beckman B177, 279 Campus Drive, Stanford CA 94305

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DEN restraints and ECHT disorder models
by Roberto Battistutta 06 Jun '26

06 Jun '26

Dear all, From which version of Phenix are the DEN restraints and ECHT disorder models implemented in the ensemble refinement (as described in Ploscariu, N., Burnley, T., Gros, P. & Pearce, N. M. (2021). Improving sampling of crystallographic disorder in ensemble refinement. Acta Cryst. D77, 1357-1364)? Thank you very much, Roberto. Roberto Battistutta Associate Professor Department of Chemical Sciences University of Padua via Marzolo 1, 35131 Padova - ITALY tel. +39.049.827.5262 fax. +39.049.827.5829 roberto.battistutta(a)unipd.it

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twinning and translational NCS issues
by Wenhui Xi 06 Jun '26

06 Jun '26

Hi all, i have this crystal which was reported severe issues with twinning and translational NCS, thus when i tried to refine its structure, the Rfree would go up to nearly 60% which making directly solving its structure very hard. i'm writing to ask are there any helpful ways to deal with this issue? Thank you! Joyce [image: image.png]

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Research Specialist Position at the University of Illinois to Study Ribosome Structure | POLIKANOV Lab
by Yury Polikanov 06 Jun '26

06 Jun '26

*Research Specialist Position Available, Department of Biological Sciences, University of Illinois at Chicago - Polikanov Lab* *The Polikanov Laboratory in the Department of Biological Sciences at the University of Illinois at Chicago (IL, USA) is looking for a talented, skillful, and highly motivated researcher to fill the Research Specialist position to study the structure and function of the bacterial ribosome.* For fullest consideration, please submit an application and cover letter describing your scientific interests and how your previous research accomplishments and scientific interests fit with the scope of the research in the Polikanov research group at https://uic.csod.com/ux/ats/careersite/1/home/requisition/7573?c=uic *Position Summary:* The research in the Polikanov Laboratory at UIC is focused on understanding the basic principles of protein synthesis in bacteria, the modes of action of ribosome-targeting antibiotics, and the mechanisms of drug resistance at a structural level. This position is involved in the determination of high-resolution structures of ribosome functional complexes with various protein translation factors, tRNAs, and antibiotics using macromolecular X-ray crystallography and potentially cryo-EM techniques. Expected contributes to the design and delivery of research projects and collaborates with researchers to develop, execute, and interpret research projects. Performs complex laboratory and data collection techniques. *Duties & Responsibilities:* - Perform research relevant to the assigned projects; - Isolate, purify, and crystallize bacterial ribosomes; - Purify all additional components necessary for the crystallization experiments, such as recombinant proteins, tRNAs; - Collect X-ray diffraction data from the ribosome crystals at the APS and NSLS-II Synchrotrons; - Perform structural data analysis; - Coordinate, analyze, and document results for publication; - Directly participate in writing papers and grants based on the experimental data; - Train undergraduate and graduate students in research methods, use of equipment, record keeping, and laboratory database entry; - Attend weekly group meetings and journal club seminars. - Perform other related duties and participate in special projects as assigned. *Minimum Qualifications:* - A bachelor’s degree in chemistry, biochemistry, biophysics, or a related field is required. - A master’s degree in chemistry, biochemistry, biophysics, or a related field is preferred. - A minimum of 3 years related research experience. - Possesses and applies comprehensive knowledge of research principles, concepts, practices, and methods. - Proficient in standard molecular biology and biochemistry lab techniques, such as protein expression, and purification *Preferred Qualifications:* - Experience in structural biology (cryo-EM or X-ray crystallography); - Experience in RNA biology, ribosome, and/or protein synthesis fields. *About the University of Illinois Chicago:* UIC is among the nation’s preeminent urban public research universities, a Carnegie RU/VH research institution, and the largest university in Chicago. UIC serves over 34,000 students, comprising one of the most diverse student bodies in the nation and is designated as a Minority Serving Institution (MSI), an Asian American and Native American Pacific Islander Serving Institution (AANAPSI) and a Hispanic Serving Institution (HSI). Through its 16 colleges, UIC produces nationally and internationally recognized multidisciplinary academic programs in concert with civic, corporate and community partners worldwide, including a full complement of health sciences colleges. By emphasizing cutting-edge and transformational research along with a commitment to the success of all students, UIC embodies the dynamic, vibrant and engaged urban university. Recent “Best Colleges” rankings published by U.S. News & World Report, found UIC climbed up in its rankings among top public schools in the nation and among all national universities. UIC has nearly 260,000 alumni, and is one of the largest employers in the city of Chicago. *The University of Illinois System is an equal opportunity employer, including but not limited to disability and/or veteran status, and complies with all applicable state and federal employment mandates. Please visit Required Employment Notices and Posters <https://www.hr.uillinois.edu/cms/one.aspx?portalId=4292&pageId=5705> to view our non-discrimination statement and find additional information about required background checks, sexual harassment/misconduct disclosures, COVID-19 vaccination requirement, and employment eligibility review through E-Verify. **The university provides accommodations to applicants and employees. Request an Accommodation <https://jobs.uic.edu/request-and-accomodation/>*

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POSITION AVAILABLE: Visiting Research Specialist Position at the University of Illinois at Chicago
by Yury Polikanov 06 Jun '26

06 Jun '26

*Visiting Research Specialist Position Available in the Polikanov Lab <https://sites.google.com/view/polikanovlab>Department of Biological Sciences, University of Illinois at Chicago* *The Polikanov Laboratory <https://sites.google.com/view/polikanovlab> in the Department of Biological Sciences at the University of Illinois at Chicago is looking for a talented, skillful, and highly motivated researcher to fill the Visiting Research Scientist position to study the structure and function of the bacterial ribosome.* For full consideration, please submit your application along with a Cover Letter, CV, and three references by May 31, 2025. Cover letter should describe previous research accomplishments and scientific interests as well as how these fit within the scope of the research in the Polikanov lab. Questions can be addressed to Yury Polikanov at yuryp(a)uic.edu. Visiting Research Specialist- UIC Department of Biological Sciences, Polikanov Lab Hiring Department: Biological Sciences Location: Chicago, IL USA Requisition ID: 1033622 Posting Close Date: 05/31/2025 Link to Apply: https://uic.csod.com/ux/ats/careersite/1/home/requisition/14681?c=uic *Position Summary:* The Polikanov Lab is seeking a Visiting Research Specialist. Successful candidate will conduct research by using X-ray crystallography and cryo-EM techniques to obtain a structural basis for various functions of the bacterial ribosome and its inhibition by different small-molecule inhibitors. The successful candidate should have a strong theoretical background in standard biochemical, molecular biology, and biophysical methods, as well as practical skills in the most standard methods currently used in molecular biology and biochemistry (such as protein expression, purification, etc.). Knowledge in X-ray crystallography or other structural techniques is desired but not required. The successful candidate would conduct research and assist with training laboratory personnel in various techniques, experiments, and the appropriate use of research equipment. He/She would also perform data analysis and manage, document, and help with the dissemination of research activities for publication and outreach. *Duties & Responsibilities:* - Record keeping: log and track inventory of chemicals, reagents, and lab supplies - Maintain accurate records of experiments, procedures, and results - Keep the laboratory clean, organized, and free of contaminants - Glassware & Equipment Maintenance - Prepare culture media, buffers, and reagents according to protocols - Assist other researchers in the lab in conducting experiments - Purify bacterial ribosomes and all additional components necessary for the experiments, such as recombinant proteins, tRNAs - Train undergraduate and graduate students in research methods, use of equipment, record keeping, and laboratory database entry *Minimum Qualifications :* - Bachelor’s degree in biology, chemistry, biochemistry, biophysics, or related field required. Master’s degree in science preferred. - A minimum of 3 years of related research experience. - Strong background in biochemistry and molecular biology - Practical skills with the most standard methods currently used in molecular biology, and biochemistry (such as protein expression, purification) *Salary:* The budgeted salary range for the position is $48,000 to $60,000. The pay offered to the selected candidate will be determined based on factors including (but not limited to) the experience and qualifications of the selected candidate, including equivalent years in rank, training, and field or discipline; internal equity; and external market pay for comparable jobs. *About the University of Illinois Chicago* UIC is among the nation’s preeminent urban public research universities, a Carnegie RU/VH research institution, and the largest university in Chicago. UIC serves over 34,000 students, comprising one of the most diverse student bodies in the nation and is designated as a Minority Serving Institution (MSI), an Asian American and Native American Pacific Islander Serving Institution (AANAPSI) and a Hispanic Serving Institution (HSI). Through its 16 colleges, UIC produces nationally and internationally recognized multidisciplinary academic programs in concert with civic, corporate and community partners worldwide, including a full complement of health sciences colleges. By emphasizing cutting-edge and transformational research along with a commitment to the success of all students, UIC embodies the dynamic, vibrant and engaged urban university. Recent “Best Colleges” rankings published by U.S. News & World Report, found UIC climbed up in its rankings among top public schools in the nation and among all national universities. UIC has over 300,000 alumni, and is one of the largest employers in the city of Chicago. Benefits eligible positions include a comprehensive benefits package which offers: Health, Dental, Vision, Life, Disability & AD&D insurance; a defined benefit pension plan; paid leaves such as Vacation, Holiday and Sick; tuition waivers for employees and dependents. Click for a complete list of *Employee Benefits <https://www.hr.uillinois.edu/benefits/>*. *Final authorization of the position is subject to availability of funding.* *UIC is an EOE including Disability/Vets.* *The University of Illinois may conduct background checks on all job candidates upon acceptance of a contingent offer. Background checks will be performed in compliance with the Fair Credit Reporting Act* *The University of Illinois System requires candidates selected for hire to disclose any documented finding of sexual misconduct or sexual harassment and to authorize inquiries to current and former employers regarding findings of sexual misconduct or sexual harassment. For more information, visit **https://www.hr.uillinois.edu/cms/One.aspx?portalId=4292&pageId=1411899 <https://www.hr.uillinois.edu/cms/One.aspx?portalId=4292&pageId=1411899>*

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Phenix 2.1-6048 macOS / REEL (eLBOW) stability issue
by Xavier Brazzolotto 04 Jun '26

04 Jun '26

Hi, Phenix users and developers Using the recent Phenix release (2.1.6048), I am experiencing stability issues when inspecting eLBOW results in the REEL interface. The REEL interface systematically closes after some manipulations, crashing the whole Phenix interface. Are any users also impacted? I am using a Phenix on a MacBook Pro M2 (Apple Silicon) Xavier

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Seeking Advice on Difficult MR Case: TFZ 6–8 for All Search Models, R-free ~0.50
by syedsuhail7654＠gmail.com 03 Jun '26

03 Jun '26

I am working on a protein containing two domains: an N-terminal FHA domain and a C-terminal RING domain. I have collected a native dataset that extends to 2.45 Å resolution in space group P2₁2₁2 with unit-cell parameters approximately a = 46.9 Å, b = 91.9 Å, c = 165.0 Å. I have been struggling to obtain a convincing molecular replacement solution despite trying multiple approaches. What I have tried so far: Full-length AlphaFold model as a search model. Splitting the AlphaFold model into individual FHA and RING domains. Sequential/domain-wise MR searches. Aggressive model trimming. Poly-alanine versions of the models. Various combinations of domain placement strategies. However, the results remain largely the same: TFZ values are consistently in the range of 6–8. LLG values are not particularly convincing. Refinement of the best solutions leads to R-free values around 0.50 or higher. Electron-density maps are not readily interpretable. No solution has shown clear evidence of being correct after refinement and map inspection. At this stage I am trying to determine whether the issue is: Failure of MR due to domain rearrangement between the FHA and RING domains. Incorrect number of molecules in the asymmetric unit. Partial placement of domains that is being missed. Crystal pathologies such as pseudo-symmetry or translational NCS. Some other issue that I may be overlooking. I would appreciate suggestions on: Additional diagnostics to assess whether any of these TFZ 6–8 solutions might actually be correct. Strategies for multi-domain MR in cases where AlphaFold-based models are unsuccessful. Whether further model editing is likely to help. Other MR pipelines that may be worth trying before moving to experimental phasing. Any advice would be greatly appreciated.

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