Hadamard conjugation can be used in the reconstruction of evolutionary trees and analysis of molecular sequence evolution. Despite the number of advantages Hadamard conjugation provides the number of evolutionary substitution models that can be used with this technique is limited. In this paper, we consider the question of whether Hadamard conjugation is limited to group-based evolutionary mode...

Bio-orthogonal chemistry has been widely used for conjugation of polymer molecules to proteins. Here, we demonstrate the conjugation of polyethylene glycol (PEG) to bovine beta-lactoglobulin (BLG) by photo-induced cyclo-addition of tetrazole-appended PEG and allyl-modified BLG. During the course of the investigation, a significant side-reaction was found to occur for the conjugation of PEG-tetr...

The syntheses of phosphatidylserine (PS) conjugates are described, including fluorescent derivatives for potential cellular delivery and bioimaging applications. Installation of terminal functional groups (amine, thiol, or alkyne) onto the sn-2 chain provides reactive sites for bio-orthogonal conjugation of cargo with suitably protected PS derivatives. An amine-containing PS forms amide bonds w...

Ubiquitin-like proteins (Ubl's) are conjugated to target proteins or lipids to regulate their activity, stability, subcellular localization, or macromolecular interactions. Similar to ubiquitin, conjugation is achieved through a cascade of activities that are catalyzed by E1 activating enzymes, E2 conjugating enzymes, and E3 ligases. In this review, we will summarize structural and mechanistic ...

All organisms are constantly and unavoidably exposed to xenobiotics including both man– made and natural chemicals such as drugs, plant alkaloids, microorganism toxins, pollutants, pesticides, and other industrial chemicals. Formally, biotransformation of xenobiotics as well as endogenous compounds is subdivided into phase I and phase II reactions. This chapter focuses on phase II biotransforma...

The cytotoxic interaction between cloned human Natural Killer (NK) cells and K562 target cells was studied using confocal laser scanning microscopy (CLSM) and conventional fluorescence microscopy. We observed, using fixed as well as living cells, the occurrence of (pseudo) emperipolesis during the interaction. About 30% of conjugated NK cells penetrated, partly or completely, into the target ce...

ISG15 is an interferon (IFN)-alpha/beta-induced ubiquitin-like protein that is conjugated to cellular proteins during innate immune responses to viral and bacterial infections. A recent proteomics study identified 158 human proteins targeted for ISG15 conjugation, including the ISG15 E1 and E2 enzymes (Ube1L and UbcH8, respectively) and a HECT E3 enzyme, Herc5. Like the genes encoding Ube1L and...

Ubiquitin conjugation is known to target protein substrates primarily to degradation by the proteasome or via the endocytic route. Here we describe a novel protein modification pathway in yeast which mediates the conjugation of RUB1, a ubiquitin-like protein displaying 53% amino acid identity to ubiquitin. We show that RUB1 conjugation requires at least three proteins in vivo. ULA1 and UBA3 are...

In this paper, the application of the double radical nucleophilic aromatic substitution (SRN1) in various dihalogenated, mostly diiodinated, π-conjugated systems as a tool for qualitatively estimating their π-conjugation is described. This approach uses electron delocalisation as a measure of π-conjugation. Electron injection into the π-system is achieved via reaction of an intermediate aryl ra...