4u15
From Proteopedia
M3-mT4L receptor bound to tiotropium
Structural highlights
Function[ACM3_RAT] The muscarinic acetylcholine receptor mediates various cellular responses, including inhibition of adenylate cyclase, breakdown of phosphoinositides and modulation of potassium channels through the action of G proteins. Primary transducing effect is Pi turnover.[1] [2] [3] Publication Abstract from PubMedG protein-coupled receptors (GPCRs) mediate the majority of cellular responses to hormones and neurotransmitters. Most GPCR crystal structures have been obtained using a fusion protein strategy where the flexible third intracellular loop is replaced by T4 lysozyme (T4L). However, wild-type T4L may not be ideally suited for all GPCRs because of its size and the inherent flexibility between the N- and C-terminal subdomains. Here we report two modified T4L variants, designed to address flexibility and size, that can be used to optimize crystal quality or promote alternative packing interactions. These variants were tested on the M3 muscarinic receptor (M3). The original M3-T4L fusion protein produced twinned crystals that yielded a 3.4 A structure from a 70 crystal data set. We replaced T4L with the modified T4L variants. Both T4L variants yielded M3 muscarinic receptor crystals with alternate lattices that were not twinned, including one that was solved at 2.8 A resolution. Modified T4 Lysozyme Fusion Proteins Facilitate G Protein-Coupled Receptor Crystallogenesis.,Thorsen TS, Matt R, Weis WI, Kobilka BK Structure. 2014 Oct 23;22(11):1657-1664. doi: 10.1016/j.str.2014.08.022. PMID:25450769[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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