التفاصيل البيبلوغرافية
| العنوان: |
GXXXG and AXXXA: Common alpha-Helical Interaction Motifs in Proteins, Particularly in Extremophiles |
| المؤلفون: |
Gary Kleiger, Robert Grothe, Parag Mallick, David Eisenberg |
| المساهمون: |
The Pennsylvania State University CiteSeerX Archives |
| المصدر: |
http://www.doe-mbi.ucla.edu/~parag/./docs/gxxxg.pdfTest. |
| سنة النشر: |
2002 |
| المجموعة: |
CiteSeerX |
| 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 nonredundant PDB set contain at least one R-helix with the GXXXG motif, 41 ±9% more than expected if glycine residues were uniformly distributed in those R-helices. More than 50% of the GXXXG-containing R-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 Calpha-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 Calpha-H.O hydrogen bonds stabilize the helix-helix interactions. In addition to the GXXXG motif, some 808 proteins from the nonredundant PDB set contain at least one R-helix with the AXXXA motif (30 ±3% greater than expected). Both the GXXXG and AXXXA motifs occur frequently in predicted R-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 th. |
| نوع الوثيقة: |
text |
| وصف الملف: |
application/pdf |
| اللغة: |
English |
| العلاقة: |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.15.1015Test; http://www.doe-mbi.ucla.edu/~parag/./docs/gxxxg.pdfTest |
| الإتاحة: |
http://www.doe-mbi.ucla.edu/~parag/./docs/gxxxg.pdfTest |
| حقوق: |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
| رقم الانضمام: |
edsbas.9F8EB5C |
| قاعدة البيانات: |
BASE |
