A family of amphiphilic dioxidovanadium(V) hydrazone complexes as potent carbonic anhydrase inhibitors along with anti-diabetic and cytotoxic activities

BioMetals - A family of dioxidovanadium(V) complexes (1–4) of the type [Na(H2O)x]+[VVO2(HL1?4)]? (x?=?4, 4.5 and 7) where HL2? represents the dianionic form of...     

Characterization of <Emphasis Type="Italic">p</Emphasis>-hydroxybenzaldehyde dehydrogenase,the final enzyme of <Emphasis Type="Italic">p</Emphasis>-hydroxybenzoic acid biosynthesis in hairy roots of <Emphasis Type="Italic">Daucus carota</Emphasis>

Hairy root cultures of Daucus carota respond to methyl-jasmonate treatment with enhanced accumulation of p-hydroxybenzoic acid. The final C₁-side chain of this compound is shaped by p-hydroxybenzaldehyde dehydrogenase (HBD) that catalyzes the formation of p-hydroxybenzoic acid from p-hydroxybenzaldehyde in the presence of NAD⁺. HBD was biochemically characterized from cell-free hairy root extracts of D. carota. The preferred substrate for HBD was p-hydroxybenzaldehyde. The apparent K _m values were 54.8 and 74.4 μM for p-hydroxybenzaldehyde and NAD⁺, respectively. Divalent metal cations did not significantly affect enzyme activity.     

Detection of in vivo protein tyrosine nitration in petite mutant of Saccharomyces cerevisiae: Consequence of its formation and significance

Protein tyrosine nitration (PTN) is a selective post-translational modification often associated with physiological and pathophysiological conditions. Tyrosine is modified in the 3-position of the phenolic ring through the addition of a nitro group. In our previous study we first time showed that PTN occurs in vivo in Saccharomyces cerevisiae. In the present study we observed occurrence of PTN in petite mutant of S. cerevisiae which indicated that PTN is not absolutely dependent on functional mitochondria. Nitration of proteins in S. cerevisiae was also first time confirmed in immunohistochemical study using spheroplasts. Using proteosomal mutants Rpn10Δ, Pre9Δ, we first time showed that the fate of protein nitration in S. cerevisiae was not dependent on proteosomal clearing and probably played vital role in modulating signaling cascades. From our study it is evident that protein tyrosine nitration is a normal physiological event of S. cerevisiae.     

The function of the PduJ microcompartment shell protein is determined by the genomic position of its encoding gene

Bacterial microcompartments (MCPs) are complex organelles that consist of metabolic enzymes encapsulated within a protein shell. In this study, we investigate the function of the PduJ MCP shell protein. PduJ is 80% identical in amino acid sequence to PduA and both are major shell proteins of the 1,2‐propanediol (1,2‐PD) utilization (Pdu) MCP of Salmonella. Prior studies showed that PduA mediates the transport of 1,2‐PD (the substrate) into the Pdu MCP. Surprisingly, however, results presented here establish that PduJ has no role 1,2‐PD transport. The crystal structure revealed that PduJ was nearly identical to that of PduA and, hence, offered no explanation for their differential functions. Interestingly, however, when a pduJ gene was placed at the pduA chromosomal locus, the PduJ protein acquired a new function, the ability to mediate 1,2‐PD transport into the Pdu MCP. To our knowledge, these are the first studies to show that that gene location can determine the function of a MCP shell protein. We propose that gene location dictates protein‐protein interactions essential to the function of the MCP shell.     

Physiological functions of D-alanine carboxypeptidases in Escherichia coli

Bacterial cell shape is, in part, mediated by the peptidoglycan (murein) sacculus. Penicillin-binding proteins (PBPs) catalyze the final stages of murein biogenesis and are the targets of beta-lactam antibiotics. Several low molecular mass PBPs including PBP4, PBP5, PBP6 and DacD seem to possess DD-carboxypeptidase (DD-CPase) activity, but these proteins are dispensable for survival in laboratory culture. The physiological functions of DD-CPases in vivo are unresolved and it is unclear why bacteria retain these seemingly non-essential and enzymatically redundant enzymes. However, PBP5 clearly contributes to maintenance of cell shape in some PBP mutant backgrounds. In this review, we focus on recent findings concerning the physiological functions of the DD-CPases in vivo, identify gaps in the current knowledge of these proteins and suggest some possible courses for future study that might help reconcile current models of bacterial cell morphology.