Barley acyl carrier protein: its amino acid sequence and assay using purified malonyl-CoA:ACP transacylase

Malonyl-CoA:ACP transacylase from barley (Hordeum vulgare L.) has been purified to homogeneity and used in an assay for acyl carrier protein (ACP). The transacylase is an acidic, monomeric protein with a molecular weight of 34,500 very similar to the analogous E. coli enzyme. A heat and acid stable acyl carrier protein from barley has been purified to homogeneity and its chemical composition determined. The ACP consists of a continuous stretch of the following 72 amino acids H2N-A-A-M-G-E-A-Q-A-K-K-E-T-V-D-K-V-(C?)-M-I-V-K-K-Q-L-A-V-P-D-G-T-P-V-T-A-E-S-K-F-S-E-L-G-A-D-S-L-D-T-V-E-I-V-M-G-L-E-E-E-F-N-I-T-V-D-E-T-S-A-Q-D-I-A72...A87-COOH. A comparison of the primary structure of this plant ACP and bacterial ACP reveals two identical sequences (underlined) in the midregion of the molecule containing the 4′-phosphopantetheine attachment site, while differences occur outside this region. Nine extra residues (italicized) are present at the N-terminal end of the barley protein thereby accounting for its larger size. Identical products are obtained when barley chloroplast fatty acid synthetase is incubated with either barley or E. coli ACP, but the latter is twice as active as the former in fatty acid synthesis. The possible significance of the N-terminal part of the ACP is discussed in relation to the reported differences in biochemical activities of plant and bacterial ACPs

Structure-function relationships of β-D-glucan endo- and exohydrolases from higher plants

Reprinted from Plant Molecular Biology, Volume 47 (1, 11),2001Maria Hrmova, Geoffrey B. Finche

Structure-function relationships of beta-D-glucan endo- and exohydrolases from higher plants

(1→3),(1→4)-β-D-Glucans represent an important component of cell walls in the Poaceae family of higher plants. A number of glycoside endo- and exohydrolases is required for the depolymerization of (1→3),(1→4)-β-Dglucans in germinated grain or for the partial hydrolysis of the polysaccharide in elongating vegetative tissues. The enzymes include (1→3),(1→4)-β-D-glucan endohydrolases (EC 3.2.1.73), which are classified as family 17 glycoside hydrolases, (1→4)-β-D-glucan glucohydrolases (family 1) and β-D-glucan exohydrolases (family 3). Kinetic analyses of hydrolytic reactions enable the definition of action patterns, the thermodynamics of substrate binding, and the construction of subsite maps. Mechanism-based inhibitors and substrate analogues have been used to study the spatial orientation of the substrate in the active sites of the enzymes, at the atomic level. The inhibitors and substrate analogues also allow us to define the catalytic mechanisms of the enzymes and to identify catalytic amino acid residues. Three-dimensional structures of (1→3),(1→4)-β-D-glucan endohydrolases, (1→4)- β-D-glucan glucohydrolases and β-D-glucan exohydrolases are available or can be reliably modelled from the crystal structures of related enzymes. Substrate analogues have been diffused into crystals for solving of the threedimensional structures of enzyme-substrate complexes. This information provides valuable insights into potential biological roles of the enzymes in the degradation of the barley (1→3),(1→4)-β-D-glucans during endosperm mobilization and in cell elongation.Maria Hrmova and Geoffrey B. Finche

Psychometric Properties and Correlates of Precarious Manhood Beliefs in 62 Nations

Precarious manhood beliefs portray manhood, relative to womanhood, as a social status that is hard to earn, easy to lose, and proven via public action. Here, we present cross-cultural data on a brief measure of precarious manhood beliefs (the Precarious Manhood Beliefs scale [PMB]) that covaries meaningfully with other cross-culturally validated gender ideologies and with country-level indices of gender equality and human development. Using data from university samples in 62 countries across 13 world regions (N = 33,417), we demonstrate: (1) the psychometric isomorphism of the PMB (i.e., its comparability in meaning and statistical properties across the individual and country levels); (2) the PMB’s distinctness from, and associations with, ambivalent sexism and ambivalence toward men; and (3) associations of the PMB with nation-level gender equality and human development. Findings are discussed in terms of their statistical and theoretical implications for understanding widely-held beliefs about the precariousness of the male gender role. © The Author(s) 2021