Sandbox Reserved 973: Difference between revisions
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in both subunits the two PAS domains are linked thanks to an ADN linker of approximately 15 residues called L2 but the conformation of this linker is very different. | in both subunits the two PAS domains are linked thanks to an ADN linker of approximately 15 residues called L2 but the conformation of this linker is very different. | ||
In CLOCK the main part of L2 is buried between the dimeric interface whereas in BMAL1 the linker is exposed on the outside and is very flexible. The PAS-B domaines are stacked in a parallel way. The sheet of BMAL1 contacts the helical face of CLOCK so several residues get hidden on CLOCK as well as on BMAL1, including Tyr310, Val315, Leu318 of the first one and Phe423, Trp427 and Val435 of the second one. Hydrophobic interactions are once more involved in the dimerization process. As an exemple, BMAL1 Trp427 located in the -sheet intrudes in a hydrophobic cleft created by the CLOCK helical face fold, where | In CLOCK the main part of L2 is buried between the dimeric interface whereas in BMAL1 the linker is exposed on the outside and is very flexible. The PAS-B domaines are stacked in a parallel way. The sheet of BMAL1 contacts the helical face of CLOCK so several residues get hidden on CLOCK as well as on BMAL1, including Tyr310, Val315, Leu318 of the first one and Phe423, Trp427 and Val435 of the second one. Hydrophobic interactions are once more involved in the dimerization process. As an exemple, BMAL1 Trp427 located in the -sheet intrudes in a hydrophobic cleft created by the CLOCK helical face fold, where it contacts the indole ring of CLOCK Trp248. | ||
Single mutations on the two PAS-B domain seem to have very limited effects on the activity even if it can raise to a 30% réduction for some aminoacids. We also observe a sensible destabilization of the PAS-B domainns interactions wich enlightens the importance of its primary structure. What's more, the double BMAL1 PAS-B domain mutant, B:F423R/V435R and the combined CLOCK:BMAL1 mutant C:W284A+B:W427A showed a decrease of the heterodomeric complex concentration and of the activity of the protrein. This result points out the importance of the contact between CLOCK Trp 248 and BMAL1 Trp 427 as ex plaines previously. | |||
== Effects on the circadian cycle== | |||
== | |||
== Structural highlights == | == Structural highlights == | ||