Porphobilinogen deaminase (PBGD) catalyzes the formation of 1-hydroxymethylbilane (HMB), a crucial intermediate in tetrapyrrole biosynthesis, through a step-wise polymerization of four molecules of porphobilinogen (PBG), using a unique dipyrromethane (DPM) cofactor. Structural and biochemical studies have suggested residues with catalytic importance, but their specific role in the mechanism and...

Quantitative real-time or kinetic RT-PCR is increasingly used for the quantification of specific mRNA targets, especially in clinical applications. To quantify the mRNA of cytokines and their receptors, which play important roles in the pathogenesis of autoimmune diseases such as multiple sclerosis, we have developed quantitative two-step RT-PCR assays for IL-4, IL-4R, IFN-gamma, IFN-beta, and ...

The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses an early step of the tetrapyrrole-biosynthesis pathway in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. The enzyme possesses a dipyrromethane cofactor, which is covalently linked by a thioether bridge to an invariant cysteine residue (Cys241 in ...

The Arabidopsis rugosa1 (rug1) mutant has irregularly shaped leaves and reduced growth. In the absence of pathogens, leaves of rug1 plants have spontaneous lesions reminiscent of those seen in lesion-mimic mutants; rug1 plants also express cytological and molecular markers associated with defence against pathogens. These rug1 phenotypes are made stronger by dark/light transitions. The rug1 muta...

Analysis of gene expression and its transcriptional regulation requires a reliable access to target mRNA. However, mRNA extractions from homogenized tissue are limited because only average data are obtained, and cell-specific expression may not be addressed. Here, we describe a new method that combines the microscopic selection of oligocellular clusters or a few isotypic cell profiles from comp...

BACKGROUND The perturbation of the steady state of reactive oxygen species (ROS) due to biotic and abiotic stresses in a plant could lead to protein denaturation through the modification of amino acid residues, including the oxidation of methionine residues. Methionine sulfoxide reductases (MSRs) catalyze the reduction of methionine sulfoxide back to the methionine residue. To assess the role o...

Porphyria is a group of eight metabolic disorders characterized by defects in heme biosynthesis. The presentation of porphyria is highly variable, and the symptoms are nonspecific, which accounts in part for delays in establishing a diagnosis. In this study, we report the characteristics of 36 Chinese acute porphyria patients. Most of them were female (33/36), and the median age was 25.3 years ...

This paper describes our contribution to the English Entrance Exams task of CLEF 2015, which requires participating systems to automatically solve multiple choice reading comprehension tasks. We use a combination of text segmentation and different similarity measures with the aim of exploiting two observed aspects of tests: 1) the often linear relationship between reading text and test question...

BACKGROUND Clinically indistinguishable attacks of acute porphyria occur in acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP). There are few evidence-based diagnostic strategies for these disorders. METHODS The diagnostic sensitivity of mutation detection was determined by sequencing and gene-dosage analysis to search for mutations in 467 sequen...