Cover Caption

About the cover: Putative structure of a regulatory domain in the amino terminus of the N-methyl-D-aspartate (NMDA) receptor NR1 subunit. The left-hand schematic shows the proposed topology of the NMDA receptor subunits with three membrane-spanning domains, a re-entrant loop, the agonist binding pocket formed by the S1-S2 domains (with the agonist shown by a gray oval), and a large extracellular amino terminus that precedes S1. The positions of amino acid residues that may form binding sites for ifenprodil (green) and spermine (yellow) are shown by circles. The right-hand schematic is a projected structure of the bacterial leucine/isoleucine/valine binding protein (LIVBP). The putative secondary structure of the amino terminus of NR1 shows considerable similarity to that of LIVBP, and this region of NR1, which is termed the R1-R2 regulatory domain, is proposed to have a tertiary structure similar to LIVBP. From Masuko T, Kashiwagi K, Kuno T, Nguyen ND, Pahk AJ, Fukuchi J-I, Igarashi K and Williams K (1999) A regulatory domain (R1-R2) in the amino terminus of the N-methyl-D-aspartate receptor: Effects of spermine, protons, and ifenprodil, and structural similarity to bacterial LIVBP. Mol Pharmacol 55:957-969.