Identification of a new nucleotide binding site by structural alignment and site directed mutagenesis
Bibliographic record
Abstract
Nucleotide binding proteins are involved in many important cellular processes and form one of the largest protein families. Traditionally, the identification of nucleotide binding motif, such as the ATP binding P-loop, has relied on the comparison of protein sequences, consideration of the function of each of the proteins and the identification of signature motifs within the sequence. Sometimes, it is difficult to identify nucleotide binding proteins based on sequence alignment because of increased evolutionary distances. In such cases, structural alignments can provide a better guide for comparing specific features of sequences because the overall structures of these motifs are conserved despite low sequence identity. In the present study, on the basis of bioinformatics and structural comparison of three representative protein structures of Ham1 superfamily, YjjX, YggV, and YhdE, previously identified as nucleotide binding proteins, we have identified a novel nucleotide binding motif (T/SXXXXK/R). The importance of this signature motif in binding of nucleotides was validated using site directed mutagenesis. Mutations of conserved residues of the loop either decreased or completely abolished the nucleotide binding activity of the protein. We used the conserved motif identified in the study to search for other proteins having a similar motif. Two proteins, GTP cyclohydrolase II and dephospho-CoA pyrophosphorylase showed presence of the loop, suggesting that this nucleotide binding motif is not unique in the Ham1 superfamily, but represents a novel NTP recognition motif.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
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) | 0.000 | 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".