“…The in vivo functions of many odorant receptors have been well established (Ai et al, 2010; Benton et al, 2009; Ha and Smith, 2006; Hallem and Carlson, 2006; Hallem et al, 2004; van der Goes van Naters and Carlson, 2007; Yao et al, 2005), but their structures are only now beginning to be solved, with the recent determination of a cryo-EM structure for an odor receptor co-receptor, Orco (Butterwick et al, 2018). Reciprocally, the structures of many Obps have been solved at high resolution (Brito et al, 2016; Kruse et al, 2003; Laughlin et al, 2008; Leite et al, 2009; Sandler et al, 2000), but their functions in vivo are much less clear (Bentzur et al, 2018; Gomez-Diaz et al, 2013; Kim et al, 1998; Larter et al, 2016; Sun et al, 2018b; Xu et al, 2005; Zhang et al, 2017).…”