Structural features of bovine colostral immunoglobulin that confer proteolytic stability in a simulated intestinal fluid.

Bovine colostral antibodies, purified from cow's milk produced immediately after calving, have enhanced resistance to degradation by intestinal proteases relative to antibodies from human or bovine serum, making them of particular interest as orally administered therapeutic agents. However, the basis of this resistance is not well defined. We evaluated the stability of AVX-470, a bovine colostral anti-tumor necrosis factor (TNF) polyclonal antibody used in early clinical studies for treatment of ulcerative colitis, using conditions that mimic the human small intestine.

Effects of AVX-470, an Oral, Locally Acting Anti-Tumour Necrosis Factor Antibody, on Tissue Biomarkers in Patients with Active Ulcerative Colitis.

Background And Aims: AVX-470 is an orally administered, bovine-derived, anti-tumour necrosis factor (TNF) antibody with local activity in the gastrointestinal tract. In the first-in-human clinical trial of AVX-470 in active ulcerative colitis, we evaluated inflammatory biomarkers in colon tissue as measures of disease activity and early response to treatment.

Methods: Thirty-six patients received active drug (AVX-470 at 0.

A microfluidic chip-compatible bioassay based on single-molecule detection with high sensitivity and multiplexing.

Many applications in pharmaceutical development, clinical diagnostics, and biological research demand rapid detection of multiple analytes (multiplexed detection) in a minimal volume. This need has led to the development of several novel array-based sensors. The most successful of these so far have been suspension arrays based on polystyrene beads.

Asymmetric interactions of ATP with the AAA+ ClpX6 unfoldase: allosteric control of a protein machine.

ATP hydrolysis by AAA+ ClpX hexamers powers protein unfolding and translocation during ClpXP degradation. Although ClpX is a homohexamer, positive and negative allosteric interactions partition six potential nucleotide binding sites into three classes with asymmetric properties. Some sites release ATP rapidly, others release ATP slowly, and at least two sites remain nucleotide free.

Nucleotide-dependent substrate recognition by the AAA+ HslUV protease.

ATP-dependent protein degradation is controlled principally by substrate recognition. The AAA+ HslU ATPase is thought to bind protein substrates, denature them, and translocate the unfolded polypeptide into the HslV peptidase. The lack of well-behaved high-affinity substrates for HslUV (ClpYQ) has hampered understanding of the rules and mechanism of substrate engagement.

Sculpting the proteome with AAA(+) proteases and disassembly machines.

Machines of protein destruction-including energy-dependent proteases and disassembly chaperones of the AAA(+) ATPase family-function in all kingdoms of life to sculpt the cellular proteome, ensuring that unnecessary and dangerous proteins are eliminated and biological responses to environmental change are rapidly and properly regulated. Exciting progress has been made in understanding how AAA(+) machines recognize specific proteins as targets and then carry out ATP-dependent dismantling of the tertiary and/or quaternary structure of these molecules during the processes of protein degradation and the disassembly of macromolecular complexes.

Effects of local protein stability and the geometric position of the substrate degradation tag on the efficiency of ClpXP denaturation and degradation.

ClpX and related AAA+ ATPases of the Clp/Hsp100 family are able to denature native proteins. Here, we explore the role of protein stability in ClpX denaturation and subsequent ClpP degradation of model substrates bearing ssrA degradation tags at different positions. ClpXP degraded T.

Energy-dependent degradation: Linkage between ClpX-catalyzed nucleotide hydrolysis and protein-substrate processing.

ClpX requires ATP to unfold protein substrates and translocate them into the proteolytic chamber of ClpP for degradation. The steady-state parameters for hydrolysis of ATP and ATPgammaS by ClpX were measured with different protein partners and the kinetics of degradation of ssrA-tagged substrates were determined with both nucleotides. ClpX hydrolyzed ATPgammaS to ADP and thiophosphate at a rate (6/min) significantly slower than ATP hydrolysis (140/min), but the hydrolysis of both nucleotides was increased by ssrA-tagged substrates and decreased by ClpP.