The Nβ motif of NaTrxh directs secretion as an endoplasmic reticulum transit peptide and variations might result in different cellular targeting.

Soluble secretory proteins with a signal peptide reach the extracellular space through the endoplasmic reticulum-Golgi conventional pathway. During translation, the signal peptide is recognised by the signal recognition particle and results in a co-translational translocation to the endoplasmic reticulum to continue the secretory pathway. However, soluble secretory proteins lacking a signal peptide are also abundant, and several unconventional (endoplasmic reticulum/Golgi independent) pathways have been proposed and some demonstrated.

The uncharacterized Pseudomonas aeruginosa PA4189 is a novel and efficient aminoacetaldehyde dehydrogenase.

Neither the Pseudomonas aeruginosa aldehyde dehydrogenase encoded by the PA4189 gene nor its ortholog proteins have been biochemically or structurally characterized and their physiological function is unknown. We cloned the PA4189 gene, obtained the PA4189 recombinant protein, and studied its structure-function relationships. PA4189 is an NAD+-dependent aminoaldehyde dehydrogenase highly efficient with protonated aminoacetaldehyde and 3-aminopropionaldehyde, which are much more preferred to the non-protonated species as indicated by pH studies.

Phosphorylation of S11 in PHR1 negatively controls its transcriptional activity.

Plant responses to phosphate starvation (-Pi) are very well characterized at the biochemical and molecular levels. The expression of thousands of genes is modified under this stress condition, depending on the action of Phosphate starvation response 1 (PHR1). Existing data indicate that neither the PHR1 transcript nor the quantity or localization of its protein increase during nutrient stress, raising the question of how its activity is regulated.

Proteolytic activities and profiles as useful traits to select barley cultivars for beer production.

Barley malting depends on hydrolytic enzymes that degrade storage macromolecules. Identifying barley cultivars with proteolytic activity that guarantees appropriate foaming, flavor, and aroma in the beer is of great importance. In this work, the proteolytic activity and profiles of brewing malt from Mexican barley cultivars were analyzed.

The critical role of the aldehyde dehydrogenase PauC in spermine, spermidine, and diaminopropane toxicity in Pseudomonas aeruginosa: Its possible use as a drug target.

The opportunistic human pathogen Pseudomonas aeruginosa exhibits great resistance to antibiotics; so, new therapeutic agents are urgently needed. Since polyamines levels are incremented in infected tissues, we explored whether the formation of a toxic aldehyde in polyamines degradation can be exploited in combating infection. We cloned the gene encoding the only aminoaldehyde dehydrogenase involved in P.

High resolution crystal structure of NaTrxh from Nicotiana alata and its interaction with the S-RNase.

Thioredoxins are regulatory proteins that reduce disulfide bonds on target proteins. NaTrxh, which belongs to the plant thioredoxin family h subgroup 2, interacts and reduces the S-RNase enhancing its ribonuclease activity seven-fold, resulting an essential protein for pollen rejection inNicotiana.Here, the crystal structure of NaTrxh at 1.

Structural and biochemical evidence of the glucose 6-phosphate-allosteric site of maize C4-phosphoenolpyruvate carboxylase: its importance in the overall enzyme kinetics.

Activation of phosphoenolpyruvate carboxylase (PEPC) enzymes by glucose 6-phosphate (G6P) and other phospho-sugars is of major physiological relevance. Previous kinetic, site-directed mutagenesis and crystallographic results are consistent with allosteric activation, but the existence of a G6P-allosteric site was questioned and competitive activation-in which G6P would bind to the active site eliciting the same positive homotropic effect as the substrate phosphoenolpyruvate (PEP)-was proposed. Here, we report the crystal structure of the PEPC-C4 isozyme from Zea mays with G6P well bound into the previously proposed allosteric site, unambiguously confirming its existence.

Identification of the allosteric site for neutral amino acids in the maize C isozyme of phosphoenolpyruvate carboxylase: The critical role of Ser-100.

The isozymes of photosynthetic phosphoenolpyruvate carboxylase from C plants (PEPC-C) play a critical role in their atmospheric CO assimilation and productivity. They are allosterically activated by phosphorylated trioses or hexoses, such as d-glucose 6-phosphate, and inhibited by l-malate or l-aspartate. Additionally, PEPC-C isozymes from grasses are activated by glycine, serine, or alanine, but the allosteric site for these compounds remains unknown.

A novel motif in the NaTrxh N-terminus promotes its secretion, whereas the C-terminus participates in its interaction with S-RNase in vitro.

Background: NaTrxh, a thioredoxin type h, shows differential expression between self-incompatible and self-compatible Nicotiana species. NaTrxh interacts in vitro with S-RNase and co-localizes with it in the extracellular matrix of the stylar transmitting tissue. NaTrxh contains N- and C-terminal extensions, a feature shared by thioredoxin h proteins of subgroup 2.

The Papaver self-incompatibility pollen S-determinant, PrpS, functions in Arabidopsis thaliana.

Many angiosperms use specific interactions between pollen and pistil proteins as "self" recognition and/or rejection mechanisms to prevent self-fertilization. Self-incompatibility (SI) is encoded by a multiallelic S locus, comprising pollen and pistil S-determinants. In Papaver rhoeas, cognate pistil and pollen S-determinants, PrpS, a pollen-expressed transmembrane protein, and PrsS, a pistil-expressed secreted protein, interact to trigger a Ca(2+)-dependent signaling network, resulting in inhibition of pollen tube growth, cytoskeletal alterations, and programmed cell death (PCD) in incompatible pollen.

A novel thioredoxin h is secreted in Nicotiana alata and reduces S-RNase in vitro.

Thioredoxins type h are classified into three subgroups. The subgroup II includes thioredoxins containing an N-terminal extension, the role of which is still unclear. Although thioredoxin secretion has been observed in animal cells, there is no evidence suggesting that any thioredoxin h is secreted in plants.