Interactions of the Disordered Domain II of Hepatitis C Virus NS5A with Cyclophilin A, NS5B, and Viral RNA Show Extensive Overlap
Bibliographic record
Abstract
Domain II of the nonstructural protein 5 (NS5A) of the hepatitis C virus (HCV) is involved in intermolecular interactions with the viral RNA genome, the RNA-dependent RNA polymerase NS5B, and the host factor cyclophilin A (CypA). However, domain II of NS5A (NS5A DII ) is largely disordered, which makes it difficult to characterize the protein–protein or protein–nucleic acid interfaces. Here we utilized a mass spectrometry-based protein footprinting approach in attempts to characterize regions forming contacts between NS5A DII and its binding partners. In particular, we compared surface topologies of lysine and arginine residues in the context of free and bound NS5A DII . These experiments have led to the identification of an RNA binding motif ( 305 RSRKFPR 311 ) in an arginine-rich region of NS5A DII . Furthermore, we show that K308 is indispensable for both RNA and NS5B binding, whereas W316, further downstream, is essential for protein–protein interactions with CypA and NS5B. Most importantly, NS5A DII binding to NS5B involves a region associated with RNA binding within NS5B. This interaction down-regulated RNA synthesis by NS5B, suggesting that NS5A DII modulates the activity of NS5B and potentially regulates HCV replication.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".