4u14
Structure of the M3 muscarinic acetylcholine receptor bound to the antagonist tiotropium crystallized with disulfide-stabilized T4 lysozyme (dsT4L)
Structural highlights
FunctionENLYS_BPT4 Endolysin with lysozyme activity that degrades host peptidoglycans and participates with the holin and spanin proteins in the sequential events which lead to the programmed host cell lysis releasing the mature viral particles. Once the holin has permeabilized the host cell membrane, the endolysin can reach the periplasm and break down the peptidoglycan layer.[1] 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.[2] [3] [4] 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[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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