Conservative Val47 residue of POU homeodomain: role in DNA recognition

Conservative Val47 residue, located in the third recognition helix of the Oct‐2 POU domain, was alternately substituted with other 19 amino acids. Affinity and specificity of interaction with oct‐site ATGCAAANGA and homeo‐specific site ATAANGA were determined for all mutants. The wild type protein (...

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Bibliographic Details
Published in:FEBS letters 1997-07, Vol.412 (1), p.5-8
Main Authors: Stepchenko, Alexander G, Luchina, Nadezda N, Polanovsky, Oleg L
Format: Article
Language:English
Subjects:
Base Sequence
Binding Sites
DNA - chemistry
DNA-Binding Proteins - chemistry
DNA-Binding Proteins - genetics
DNA-Binding Proteins - metabolism
Homeo-specific site
Homeodomain Proteins - chemistry
Mutagenesis, Site-Directed
Oct-2 protein
Oct-sequence
POU domain mutants
Protein Structure, Secondary
Protein-DNA recognition
Structure-Activity Relationship
Transcription Factors
Valine
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Summary:Conservative Val47 residue, located in the third recognition helix of the Oct‐2 POU domain, was alternately substituted with other 19 amino acids. Affinity and specificity of interaction with oct‐site ATGCAAANGA and homeo‐specific site ATAANGA were determined for all mutants. The wild type protein (with Val47) has maximal affinity and specificity in POU domain interaction with octamer sequence. However, V47I mutant showed stronger interaction with homeo‐specific site. The highest specificity of interaction with homeo‐site was recorded for V47S mutant. We conclude that only Val47 provides sequence‐specific high‐affinity binding of POU proteins with octamer targets other than the homeo‐specific site. It is shown also that damages caused by point mutations may be at least partially compensated by participation in the oct‐site recognition of both POUh and POUs domains.
ISSN:0014-5793
1873-3468
DOI:10.1016/S0014-5793(97)00508-5