Conservation and divergence on plant seed 11S globulins based on crystal structures.

The crystal structures of two pro-11S globulins namely: rapeseed procruciferin and pea prolegumin are presented here. We have extensively compared them with the other known structures of plant seed 11S and 7S globulins. In general, the disordered regions in the crystal structures among the 11S globulins correspond to their five variable regions. Variable region III of procruciferin is relatively short and is in a loop conformation. This region is highly disordered in other pro-11S globulin crystals. Local helical and strand variations also occur across the group despite general structure conservation. We showed how these variations may alter specific physicochemical, functional and physiological properties. Aliphatic hydrophobic residues on the molecular surface correlate well with Tm values of the globulins. We also considered other structural features that were reported to influence thermal stability but no definite conclusion was drawn since each factor has additive or subtractive effect. Comparison between proA3B4 and mature A3B4 revealed an increase in r.m.s.d. values near variable regions II and IV. Both regions are on the IE face. Secondary structure based alignment of 11S and 7S globulins revealed 16 identical residues. Based on proA3B4 sequence, Pro60, Gly128, Phe163, Phe208, Leu213, Leu227, Ile237, Pro382, Val404, Pro425 and Val 466 are involved in trimer formation and stabilization. Gly28, Gly74, Asp135, Gly349 and Gly397 are involved in correct globular folding.

Clinical predictive factors for preterm birth in women with threatened preterm labour or preterm premature ruptured membranes?

BACKGROUND: Independent predictive factors of preterm delivery were evaluated using clinical data at hospitalisation by multivariate analysis. AIM: The aim of this study was to clarify independent predictive factors related to preterm delivery by multivariate analysis of clinical data at hospitalisation of patients with threatened preterm delivery or premature rupture of membranes (PROM), and to realise the early and highly reliable prediction of preterm delivery in pregnant women at risk. METHODS: The subjects were 200 patients, which diagnosed with threatened preterm delivery or PROM and admitted at gestational ages of 22-35 weeks. Univariate and multivariate analyses were performed; 20 factors were evaluated concerning clinical data, and we extracted prognostic factors using logistic regression analysis. RESULTS: The mean age of the patients was 30.5 years, and the mean gestational age at admission was 30.0 weeks. Preterm delivery was observed in 55 (27.5%), and term delivery in 145 (72.5%). On multivariate analysis, haemorrhage, prepregnancy body mass index, fetal fibronectin and cervical length were extracted as independent predictive factors related to preterm delivery. CONCLUSIONS: If the reliable and reproducible prediction of preterm delivery becomes possible using the four factors extracted in this study, further evaluation of these factors may lead to clarification of the mechanism of preterm delivery.

Development of transgenic rice containing a mutated beta subunit of soybean beta-conglycinin for enhanced phagocytosis-stimulating activity.

Improving the nutraceutical value of rice would positively impact the health and well-being of rice consumers worldwide. Based on the three-dimensional structure of soybean beta-conglycinin, we designed a beta subunit with a strong phagocytosis-stimulating activity (mbeta subunit). Here, we describe the genetic modification and production of rice seeds containing the mbeta subunit as part of our aim to develop a food material that promotes human health. The mbeta subunit folded correctly and was accumulated in the protein body II of rice seeds at a level similar to wild-type beta subunit. Mutant beta subunit purified from transgenic rice seeds exhibited high phagocytosis-stimulating activity, demonstrating its potential value in enhancing the nutritional value of rice.

Carbohydrate moieties contribute significantly to the physicochemical properties of french bean 7s globulin phaseolin.

We have previously reported that the solubility of French bean 7S globulin (phaseolin) at low ionic strength and its emulsifying stability are remarkably high compared with those of 7S globulins prepared from other plant species, including soybean (Kimura et al. J. Agric. Food Chem. 2008, 56, 10273-10279). In this study, we examined the role of carbohydrate moieties in the properties of phaseolin. Three preparations of phaseolin were analyzed: (i) N7S, prepared from defatted seed meal and having intact carbohydrate moieties; (ii) R7S, expressed in E. coli and lacking N-linked glycans; and (iii) EN7S, having partial N-linked glycans after treatment with Endo H. The solubilities of N7S and EN7S were much higher than that of R7S at a low ionic strength (micro = 0.08). N7S exhibited good emulsifying ability under the conditions examined, but R7S did not. In terms of emulsion stability, an emulsion of R7S separated into two phases after 1 h at micro = 0.01, 0.08, and 0.5, whereas the emulsion of N7S was stable for 5 days at micro = 0.01 and for at least 10 days at micro = 0.08 and 0.5. The emulsion stability of EN7S was comparable to that of N7S under most conditions examined. These results indicate the carbohydrate modifications are necessary for the good solubility, emulsifying ability, and emulsion stability of phaseolin. Further, a structural analysis of the carbohydrate moieties indicates that truncated carbohydrate moieties are sufficient for conferring these physicochemical properties to phaseolin.

Comparison of physicochemical properties of 7S and 11S globulins from pea, fava bean, cowpea, and French bean with those of soybean--French bean 7S globulin exhibits excellent properties.

Legume seeds contain 7S and/or 11S globulins as major storage proteins. The amino acid sequences of them from many legumes are similar to each other in the species but different from each other, meaning that some of these proteins from some crops exhibit excellent functional properties. To demonstrate this, we compared protein chemical and functional properties (thermal stability, surface hydrophobicity, solubility as a function of pH, and emulsifying properties) of these proteins from pea, fava bean, cowpea, and French bean with those of soybean as a control at the same conditions. The comparison clearly indicated that the 7S globulin of French bean exhibited excellent solubility (100%) at pH 4.2-7.0 even at a low ionic strength condition (mu = 0.08) and excellent emulsion stability (a little phase separation after 3 days) at pH 7.6 and mu = 0.08, although the emulsions from most of the other proteins separated in 1 h. These results indicate that our assumption is correct.

A high temperature-sensitive mutant of Synechococcus sp. PCC 7002 with modifications in the endogenous plasmid, pAQ1.

To study thermal adaptations in the cyanobacterium, Synechococcus sp. PCC 7002, we screened about 3,000 mutants for their tolerance to high temperature, and found one, SHT1, that is sensitive to high-temperature stress. The mutant had a modified gene construct in the endogenous plasmid, pAQ1. One of the four ORFs, ORF93, was duplicated, and its mRNA level was higher than in the wild type. At 38 degrees C, the growth of SHT1 was retarded as compared with the wild type, and above 38 degrees C, almost all the cells of SHT1 died. This temperature is much lower than that required for induction of heat shock proteins. Interestingly, in both the wild type and SHT1, the thermal stability of oxygen-evolving machinery increased upon acclimation to high temperatures. These findings indicate that the lack of thermal tolerance in the SHT1 strain is likely independent of the adaptation of the PSII complex and heat shock responses, whereas there are essential contributions of genes in the endogenous plasmid to the adaptation to high temperature. Thus, understanding the role of pAQ1 in the adaptation of Synechococcus sp. PCC 7002 to high-temperature environments is the first step in elucidating the function of this plasmid.

Protection of the oxygen-evolving machinery by the extrinsic proteins of photosystem II is essential for development of cellular thermotolerance in Synechocystis sp. PCC 6803.

The oxygen-evolving machinery of photosystem II in cyanobacteria is associated with three extrinsic proteins: the manganese-stabilizing protein, cytochrome c(550), and PsbU. To elucidate the effect of the presence of these extrinsic proteins on the stabilization of the oxygen-evolving machinery against high-temperature stress, we inactivated the genes for these proteins individually in Synechocystis sp. PCC 6803 by targeted mutagenesis. The thermal stability of the oxygen-evolving machinery decreased in all mutated cells but the extent of the susceptibility to heat inactivation varied between the photosystems lacking the different extrinsic proteins. Cells that lacked either the manganese-stabilizing protein or cytochrome c(550) were unable to enhance the thermal stability of the oxygen-evolving machinery and, moreover, failed to increase cellular thermotolerance when grown at moderately high temperatures. Our findings indicate that the three extrinsic proteins stabilize the oxygen-evolving machinery independently against high-temperature stress and that the thermal stability of the machinery influences cellular thermotolerance.