GXXXG and AXXXA: Common α-Helical Interaction Motifs in Proteins, Particularly in Extremophiles
| العنوان: | GXXXG and AXXXA: Common α-Helical Interaction Motifs in Proteins, Particularly in Extremophiles |
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| المؤلفون: | Gary Kleiger, Parag Mallick, David Eisenberg, Robert Grothe |
| المصدر: | Biochemistry. 41:5990-5997 |
| بيانات النشر: | American Chemical Society (ACS), 2002. |
| سنة النشر: | 2002 |
| مصطلحات موضوعية: | Models, Molecular, biology, Stereochemistry, Dimer, Amino Acid Motifs, Protein Data Bank (RCSB PDB), Proteins, Transposases, Hydrogen Bonding, Biochemistry, Protein Structure, Secondary, Recombinases, chemistry.chemical_compound, Transmembrane domain, Crystallography, Protein structure, chemistry, Membrane protein, biology.protein, Thermodynamics, Glycophorin, Amino Acid Sequence, Glycophorins, Sequence motif, Peptide sequence |
| الوصف: | The GXXXG motif is a frequently occurring sequence of residues that is known to favor helix-helix interactions in membrane proteins. Here we show that the GXXXG motif is also prevalent in soluble proteins whose structures have been determined. Some 152 proteins from a non-redundant PDB set contain at least one alpha-helix with the GXXXG motif, 41 +/- 9% more than expected if glycine residues were uniformly distributed in those alpha-helices. More than 50% of the GXXXG-containing alpha-helices participate in helix-helix interactions. In fact, 26 of those helix-helix interactions are structurally similar to the helix-helix interaction of the glycophorin A dimer, where two transmembrane helices associate to form a dimer stabilized by the GXXXG motif. As for the glycophorin A structure, we find backbone-to-backbone atomic contacts of the C alpha-H...O type in each of these 26 helix-helix interactions that display the stereochemical hallmarks of hydrogen bond formation. These glycophorin A-like helix-helix interactions are enriched in the general set of helix-helix interactions containing the GXXXG motif, suggesting that the inferred C alpha-H...O hydrogen bonds stabilize the helix-helix interactions. In addition to the GXXXG motif, some 808 proteins from the non-redundant PDB set contain at least one alpha-helix with the AXXXA motif (30 +/- 3% greater than expected). Both the GXXXG and AXXXA motifs occur frequently in predicted alpha-helices from 24 fully sequenced genomes. Occurrence of the AXXXA motif is enhanced to a greater extent in thermophiles than in mesophiles, suggesting that helical interaction based on the AXXXA motif may be a common mechanism of thermostability in protein structures. We conclude that the GXXXG sequence motif stabilizes helix-helix interactions in proteins, and that the AXXXA sequence motif also stabilizes the folded state of proteins. |
| تدمد: | 1520-4995 0006-2960 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::80b8c6ad60b41b6c56213b7c84e4cb8dTest https://doi.org/10.1021/bi0200763Test |
| رقم الانضمام: | edsair.doi.dedup.....80b8c6ad60b41b6c56213b7c84e4cb8d |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15204995 00062960 |
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