2.7.1.175 ? x * 49800, His-tagged enzyme, sequence calculation, x * 62000, recombinant His-tagged enzyme, SDS-PAGE 717739 2.7.1.175 ? x * 52400, His-tagged enzyme, sequence calculation, x * 53000, recombinant His-tagged enzyme, SDS-PAGE -, 717739 2.7.1.175 monomer 1 * 50700, recombinant His-tagged Mak, SDS-PAGE 717432 2.7.1.175 monomer 1 * 57000, SDS-PAGE 717163 2.7.1.175 additional information in the TreS:Pep2 complex crystal, diamond-shaped TreS tetramer forms the core of the complex and pairs of Pep2 monomers bind to opposite apices of the tetramer in a 4 + 4 configuration, but the prevalent stoichiometry in solution is 4 TreS + 2 Pep2 protomers. The behavior in the solution state may be explained by the relatively weak affinity of Pep2 for TreS (Kd 3.5 microM at mildly acidic pH) and crystal packing favoring the 4 + 4 complex. Pep2 forms intimate contacts with the TreS tetramer, revealing a high level of shape complementarity between the binding partners. Structure model, overview. Secondary structure elements contributing to the binding interface are helices alpha5, alpha6, and alpha10 in the C-terminal lobe of Pep2, and contacts made by the N-terminal lobe include residues in helix alpha2, in strand beta8, and in the beta9-beta10 loop. In addition, contacts also involve the beta12-alpha5 loop, which links the N- and C-terminal lobes. The binding interface is dominated by van der Waals and hydrophobic contacts, corresponding to about 70% of surface area buried in the interface per Pep2 monomer -, 759499 2.7.1.175 additional information Pep2 forms a heterooctameric complex with trehalose synthase TreS, the complex formation markedly accelerates the maltokinase activity of Pep2 -, 737320 2.7.1.175 additional information the N-terminal lobe can be divided into two subdomains: a cap N-terminal subdomain comprising the first 88 amino acid residues and an intermediate subdomain composed of an anti-parallel beta-sheet flanked by two helices. The C-terminal lobe is mostly alpha-helical. While the N-terminal cap subdomain and the C-terminal lobe are predominantly acidic, the intermediate subdomain is enriched in positively charged residues. The N-terminal cap subdomain is composed of three long antiparallel beta-strands forming a curved beta-sheet that encloses the N-terminal alpha-helix and a short two-stranded beta-sheet running perpendicular to the longest beta-sheet axis, on its concave surface. The intermediate subdomain (residues 89-200) contains a central seven-stranded beta-sheet flanked by two alpha-helical segments. A nine-residue linker (residues 201-209) containing a short beta-strand connects the intermediate subdomain and the C-terminal lobe. This last domain is composed of two central 4-helical bundles, a short beta-hairpin and a small two-stranded beta-sheet -, 739666 2.7.1.175 trimer or tetramer x * 52000, ultracentrifugation -, 737320