Eucaryotic organisms

Homeodomain proteins are involved in the development of many eucaryotic organisms... 

TFIIA and TFIIB bind to both TBP and DNA Flomeodomain proteins are involved in the development of many eucaryotic organisms Monomers of homeodomain proteins bind to DNA through a heltx-turn-helix motif In vivo specificity of homeodomain... 

A knowledge of modification and restriction systems is of considerable practical utility in studying DNA chemistry. So far, no evidence exists that either modification or restriction occurs in eucaryotic organisms. 

The principle means by which the activity of sequence-specific DNA-binding proteins is controlled have aheady been presented in section 1.2. The importance of these mechanisms for regulation in eucaryotes will be discussed below. Altogether, the demands on eucaryotic organisms with regard to the regulation of transcription activity are much more complex than for procaryotes. This tenet holds for the structure of the transcription apparatus as well as for the mechanism of transcription regulation. 

The crystal structure of Na+/K+-ATPase, the enzyme responsible for maintaining Na+/K+ nonequilibrium in most eucaryotic organisms was determined 2007.5 The enzyme is difficult to purify since it is membrane-bound and has a high molecular mass (294 kDa). It is a heterodimer made up of... 

DNA (deoxyribonucleic acid) is well known as the molecule that bears all of the genetic information necessary to construct and operate a living organism. The cell nuclei of all eucaryotic organisms contain DNA and each cell contains all the genetic code needed to assemble the entire organism - a remarkable duplication of information. The amount of information involved requires the individual DNA... 

Figure 1. The ubiquitous high- and low-molecular-weight biopol3nner PHB is a microbial storage material (carbon and reductase equivalents, cf. Figure 2) and is found as part of ion-transporting systems in procaryotic and eucaryotic organisms, respectively [2].

In recent years several bacterial proteins have been isolated that contain a pterin that is similar but not identical to molybdopterin from eucaryotic organisms (1) (33, 41-43). These bactopterins (44) have been shown to be molybdopterin dinucleotides (e.g., 6 is the oxidized... 

The physiological roles of ascorbic acid have not yet been described in a manner that is scientifically satisfactory. The presence of ascorbic acid in all eucaryote organisms suggests fundamental roles that are not understood. The absence of ascorbic acid in procaryote organisms suggests an unknown fundamental difference between these two classes of organisms in which ascorbic acid plays an essential role. 

Calcification in eucaryotic organisms is frequently related to the Golgi apparatus (see review by Barley, 1974 and Degens, 1976). The Golgi and/or dictyosomes are defined areas of the cytoplasm and endoplasmic reticulum... 

Sorghum bicolor oxynitrilase was purified and characterised, but a functional overexpression has failed to date. The core protein was expressed correctly, but the posttranslational processing (glycosylation) could not be performed in the host organisms used. Since plants differ in the manner of glycosylation compared to simple eucaryotic organisms, functional overexpression of the oxynitrilase from Sorghum bicolor seems not to be possible in the foreseeable future [67]. 

B-Lactam Antibiotics. — Using cell-free preparations of eucaryotic organisms, e.g., Cephalosporium acremonium, it has very clearly been shown that the biosynthesis of penicillins involves the cyclisation of an intact molecule of the tripeptide (138) to give isopenicillin N (139) (cf. Vol. 12, p.25). Streptomyces clavuligerus is a procaryotic organism which produces 6-lactam antibiotics. A cell-free preparation of this organism has been obtained which would convert (138) into (139) ... 

Antisense is by no means an artificial concept. Apart from basic coding/non-coding strand interactions, a series of cases has been found in nature, in which gene regulation is effected by antisense-type nucleic acid/nucleic acid interactions. Frequently, control of translation and accelerated depletion of target mRNA is effected by antisense ODNs in eucaryotic organisms like yeast, insects or mammals. In Table 2 a series of reported natural sense/antisense interaction is listed. In case given, sequences involved in such interactions are also potential elements of therapeutic antisense action. 

There is evidence that in eucaryotic organisms other than plants the fatty acid synthase enzymes are associated in a complex in which several functions exist in a single protein. The synthase in animal liver has been shown to be a complex of two identical... 

The Cu2Zu2 enzymes can be obtained from many sources. Apart from two exceptionsthey are exclusively found in eucaryotic organisms in nearly all tissues Only the enzymes from higher species have a blocked N-terminal group. These enzymes are generally more stable. Whether this phenomenon can be ascribed to the acetylation or not is still open to discussion. Iron SOD s are exclusively prokaryotic, whereas manganese superoxide dismutases are present in procaryotic cells as well as in mitochrondria and the serum of vertebrates Their relative molecular... 

Eucaryotic organisms can be either unicellular (e.g. protozoa) or more complex structures. They all contain organelles such as mitochondria, ribosomes (also found in procaryotes), lysosomes, and plastids. Yeasts are unicellular fungi... 

Only the plant pathogen Corynebacterium fascians has so far been reported to reduce lAA to tryptophol [12]. The inverse oxidation, however, appears to be common in bacteria and eucaryotic organisms [14, 21, 29, 30]. So the reduction of indoleacetaldehyde must be reversible. Tryptophol could, however, accumulate in... 

The properties of the enzyme chorismate mutase have been similarly further examined in a variety of organisms and a remarkable diversity of properties has been demonstrated. In Escherichia coli, Aerobacter aerogenes and Salmonella typhimurium, two enzymes function in the utilisation of chorismate for the biosynthesis of L-phenylalanine and L-tyrosine but in a munber of eucaryotic organisms there appears to exist only one chorismate mutase which does not carry prephenate dehydratase or prephenate... 

Histones are the basic proteins associated with the DNA of chromosomes of virtually all eucaryotic organisms. These proteins are remarkably similar In all organisms (amino acid sequence etc.). Five types of histones, classified according to their amino acid composition, are known (Table 9.1). Their sequences have all been determined, and they show that the basic amino acids are concentrated in one half of the molecule. The fact that they differ so little from one species to another suggests that they are indispensable for maintenance of eucaryotic chromosome structure. They are present In about equimolar amounts. 

Table 7.1 shows 61 codons used to code for 20 amino adds. As can be seen, some amino acids have several different codes. In addition to the codons shown in the table there are three more codes from the permuations of four bases UAA, UGA and UAG. These codons are stop signals indicating where the ribosome should stop translating the RNA since the G-terminus of the protein has been reached. Methionine is one of two amino adds which have only one codon. In addition, it shares this codon with a start signal indicating where the N-terminus of a protein is thus all proteins in eucaryotes (organisms with complex cell stmctures) have methionine at their N-terminus. The methionine is usually removed post-translationally. 

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