A rational approach towards successful crystallization and crystal treatment of human cytomegalovirus protease and its inhibitor complex
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
The crystallization and subsequent crystal treatment of both free human cytomegalovirus (hCMV) protease and its inhibitor complexes are reported. For free-enzyme crystals, diffraction was greatly improved by optimizing the crystallization conditions, raising the precipitant concentration in the reservoir and soaking the crystals in artificial mother liquors. Each of the six components in the final crystallization formula (16% PEG 4000, 0.1 M MES pH 6.0, 0.4 M LiCl, 10% glycerol, 5% t-butanol and 5 mM Na(2)S(2)O(3)) plays a distinctive role and is indispensable. A synergistic effect of Na(2)SO(4) and t--butanol on diffraction was observed and studied. A 2.0 A multiwavelength anomalous diffraction (MAD) data set was collected using a synchrotron-radiation source, leading to the elucidation of the three-dimensional structure of the enzyme. For the inhibitor-complex crystals, initial attempts with co-crystallization and soaking experiments at pH 6.0 did not produce conclusive results. Subsequently, experiments were designed to co-crystallize the complex at pH 8.0, the optimal pH for the enzyme and the inhibitor activity. Using 20-50 mM spermine in the crystallization buffer, crystals of two peptidomimetic inhibitor complexes were obtained at pH 7.5 and 8.0. Spermine was required for the inhibitor complexes to be crystallized at pH 8.0, possibly neutralizing net negative charges of hCMV protease owing to its acidic pI of 5.5. A 2.7 A data set was collected from one of the inhibitor complexes and the structure was determined using the molecular-replacement method.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it