A review of floating semisubmersible hull systems:Column stabilized unit

Abstract Column stabilized semisubmersible is one of the most commonly used hull systems for the design and development of drilling and production platforms used for offshore deep water operations. Recent reconfiguration and design alterations have improved its hydrodynamic behaviour in rough weather conditions and, thus, its application and functionality in ocean engineering. Semisubmersible dry-trees applications and large wind turbine foundation systems in ultra-deep waters require high payload integration for reduced motion responses in all degrees of freedom. This paper presents a review of recent industrial and academic contributions to the development of column stabilized semisubmersible hulls used for deep water operations. It also provides an overview of the motion and structural attachments of semisubmersibles. The type and formation of dry-trees semisubmersibles are discussed. The dynamic behaviour and comparative advantages of them are also explained

Impact of Chemical Cross-Linking on Protein Structure and Function

Chemical cross-linking coupled with mass spectrometry is a popular technique for deriving structural information on proteins and protein complexes. Also, cross-linking has become a powerful tool for stabilizing macromolecular complexes for single-particle cryo-electron microscopy. However, an effect of cross-linking on protein structure and function should not be forgotten, and surprisingly, it has not been investigated in detail so far. Here, we used kinetic studies, mass spectrometry, and NMR spectroscopy to systematically investigate an impact of cross-linking on structure and function of human carbonic anhydrase and alcohol dehydrogenase 1 from <i>Saccharomyces cerevisiae</i>. We found that cross-linking induces rather local structural disturbances and the overall fold is preserved even at a higher cross-linker concentration. The results establish general experimental conditions for chemical cross-linking with minimal effect on protein structure and function

Aspartic Protease Nepenthesin‑1 as a Tool for Digestion in Hydrogen/Deuterium Exchange Mass Spectrometry

Hydrogen/deuterium exchange coupled to mass spectrometry (HXMS) utilizes enzymatic digestion of proteins to localize the information about altered exchange patterns in protein structure. The ability of the protease to produce small peptides and overlapping fragments and provide sufficient coverage of the protein sequence is essential for localizing regions of interest. Recently, it was shown that there is an interesting group of proteolytic enzymes from carnivorous pitcher plants of the genus <i>Nepenthes</i>. In this report, we describe successful immobilization and the use of one of these enzymes, nepenthesin-1, in HXMS workflow. In contrast to pepsin, it has different cleavage specificities, and despite its high inherent susceptibility to reducing and denaturing agents, it is very stable upon immobilization and withstands even high concentration of guanidine hydrochloride and reducing agents. We show that denaturing agents can alter digestion by reducing protease activity and/or substrate solubility, and additionally, they influence the trapping of proteolytic peptides onto the reversed phase resin

Structural Characterization of Monoclonal Antibodies and Epitope Mapping by FFAP Footprinting

Covalent labeling in combination with mass spectrometry is a powerful approach used in structural biology to study protein structures, interactions, and dynamics. Recently, the toolbox of covalent labeling techniques has been expanded with fast fluoroalkylation of proteins (FFAP). FFAP is a novel radical labeling method that utilizes fluoroalkyl radicals generated from hypervalent Togni reagents for targeting aromatic residues. This report further demonstrates the benefits of FFAP as a new method for structural characterization of therapeutic antibodies and interaction interfaces of antigen–antibody complexes. The results obtained from human trastuzumab and its complex with human epidermal growth factor receptor 2 (HER2) correlate well with previously published structural data and demonstrate the potential of FFAP in structural biology

Chemical Cross-Linking and H/D Exchange for Fast Refinement of Protein Crystal Structure

A combination of chemical cross-linking and hydrogen–deuterium exchange coupled to high resolution mass spectrometry was used to describe structural differences of NKR-P1A receptor. The loop region extended from the compact core in the crystal structure was found to be closely attached to the protein core in solution. Our approach has potential to refine protein structures in solution within a few days and has very low sample consumption

Effect of quambalarine B (2) and mompain (3) on the adenocarcinoma cell line HeLa.

<p>0.25% DMSO was used as a solvent and as a control. Upper panels: visualization of mitochondria using MitoTracker Red CMXRos (red), actin cytoskeleton using Phalloidin (green), lysosomes using monoclonal antibody MEM 259 recognizing the lysosomal protein LAMP2 (white) and nuclei with DAPI (blue). Lower panels: simultaneous visualization of mitochondria, lysosomes and nuclei only.</p

Left column: Structural formulas, FTMS data, and physical characteristics of naphthoquinones isolated from submerged culture of <i>Quambalaria cyanescens</i>; right column: X-ray structures, the displacement ellipsoids are drawn on 50% probability level.

<p>Left column: Structural formulas, FTMS data, and physical characteristics of naphthoquinones isolated from submerged culture of <i>Quambalaria cyanescens</i>; right column: X-ray structures, the displacement ellipsoids are drawn on 50% probability level.</p