MBB331_Week10-Fall-2011

2 3 transcription factor families transcription

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Unformatted text preview: mon eukaryotic Common helix-turn-helix factors: homeodomain developmental regulators regulators Weaver 2002 Molecular Biology Ed. 2 3 TRANSCRIPTION FACTOR FAMILIES: TRANSCRIPTION HOMEODOMAIN MOTIFS • Homeodomain (homeobox): 60 amino acid sequence first seen in the gene products of Drosophila Drosophila homeotic loci, mutations in which cause transformations of 1 body part into another - often involved in developmental regulation-found in many eukaryotes many • Homeodomain sometimes combined Homeodomain with other motifs - eg. Oct proteins which bind to eg Oct octamer motif --> Pou motif + homeodomain homeodomain Antennapedia 4 TRANSCRIPTION FACTOR FAMILIES: TRANSCRIPTION HOMEODOMAIN MOTIFS -homeodomains have 3 helical regions, the best conserved between different homeodomains being helix 3 -homeodomain helix 3 functions like the λ repressor recognition helix but is larger (17 amino acids compared to 9) Weaver 2002 Molecular Biology Ed. 2 5 HYDROGEN BONDS BETWEEN λ REPRESSOR & OPERATOR DNA REPRESSOR OL1 Weaver 2002 Molecular Biology Ed. 2 • in addition to hydrogen bonding, helix-2 undergoes ionic interactions in with phosphate backbone due to fact that its amino end, which has a net positive charge, is pointing directly towards negatively charged DNA backbone DNA 6 TRANSCRIPTION FACTOR FAMILIES: TRANSCRIPTION HOMEODOMAIN MOTIFS • • Homeodomain C-term region: Homeodomain helix-turn-helix motif (like λ cI repressor) repressor) crystal structure of crystal...
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This note was uploaded on 03/26/2014 for the course MBB 321 taught by Professor Davidson during the Spring '11 term at Simon Fraser.

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