I read this book the same weekend that the Packers took on the Rams, and the experience of the latter event, obviously, colored my judgment. Although I abhor anything that smacks of being a handbook (like, \"How to Earn a Merit Badge in Neurosurgery\") because too many volumes in biomedical science already evince a boyscout-like approach, I must confess that parts of this volume are fast, scholarly, and significant, with certain reservations. I like parts of this well-illustrated book because Dr. Sj6strand, without so stating, develops certain subjects on technique in relation to the acquisition of judgment and sophistication. And this is important! So, given that the author (like all of us) is somewhat deficient in some areas, and biased in others, the book is still valuable if the uninitiated reader swallows it in a general fashion, realizing full well that what will be required from the reader is a modulation to fit his vision, propreception, adaptation and response, and the kind of problem he is undertaking. A major deficiency of this book is revealed by comparison of its use of physics and of chemistry to provide understanding and background for the application of high resolution electron microscopy to problems in biology. Since the volume is keyed to high resolution electron microscopy, which is a sophisticated form of structural analysis, but really morphology in a modern guise, the physical and mechanical background of The instrument and its ancillary tools are simply and well presented. The potential use of chemical or cytochemical information as it relates to biological fine structure , however, is quite deficient. I wonder when even sophisticated morphol-ogists will consider fixation a reaction and not a technique; only then will the fundamentals become self-evident and predictable and this sine qua flon will become less mystical. Staining reactions (the most inadequate chapter) ought to be something more than a technique to selectively enhance contrast of morphological elements; it ought to give the structural addresses of some of the chemical residents of cell components. Is it pertinent that auto-radiography gets singled out for more complete coverage than other significant aspects of cytochemistry by a high resolution microscopist, when it has a built-in minimal error of 1,000 A in standard practice? I don't mean to blind-side (in strict football terminology) Dr. Sj6strand's efforts for what is \"routinely used in our laboratory\"; what is done is usually well done. It's just that …

Methods in Enzymology.

Publisher Summary This chapter discusses the fundamental molecular properties of avidin and streptavidin. Carbohydrate-free avidin can be obtained by use of deglycosylating enzymes and it has been shown to be present in significant amounts in some commercial preparations from which it may be separated by use of lectin columns. Improvement on the original use of biotinyl cellulose came with the introduction of iminobiotinyl derivatives of Sepharose that utilized the pH dependence of the binding 24 to achieve efficient elution. In iminobiotin, the ureido group becomes a guanidinium group; the form in which this is uncharged is strongly bound. The gene for streptavidin has been cloned and sequenced with the ultimate objective of using it in general expression systems for detecting and isolating fusion proteins. The stability is greatly enhanced by biotin binding, because the total free energy of binding is about 330 kJ/mol of tetramer. The dissociation constant for biotin is so low that it can be estimated only from the ratio of the rate constants for binding and exchange. The binding is accompanied by a red shift of the tryptophan spectrum and by a decrease in fluorescence, either of which can be used as the basis for quantitative assays.

Avidin and streptavidin.

Cet article synthetise les connaissances sur le repliement et l'oligomerisation des proteines du reticulum endoplasmique: proteines membranaires, glycoproteines, proteines de liaison

Protein oligomerization in the endoplasmic reticulum

Interior and surface of monomeric proteins.

Article synthese sur l'α1-antitrypsine: caracteristiques structurales et fonctionnelles (capacite de liaison a des modulateurs); utilisation de l'α1-antitrypsine en tant que modele pour toutes les serpines

Implications of the three-dimensional structure of alpha 1-antitrypsin for structure and function of serpins.

The complex of retinol with its carrier protein, retinol-binding protein (RBP) has been crystallized and its three-dimensional structure determined using X-ray crystallography Its most striking feature is an eight-stranded up-and-down beta barrel core that completely encapsulates the retinol molecule The retinol molecule lies along the axis of the barrel with the beta-ionone ring innermost and the tip of the isoprene tail close to the surface

The three-dimensional structure of retinol-binding protein.

https://www.cell.com/cell/pdf/0092-8674(82)90021-6.pdf

Alpha chain of HLA-DR transplantation antigens is a member of the same protein superfamily as the immunoglobulins

The HLA-D locus in the major histocompatibility complex controls the expression of the genetically polymorphic HLA-DR antigens. mRNA coding for the beta chains of these antigens was partially purified from the human lymphoblastoid cell line Raji. The mRNA was copied into double-stranded cDNA and cloned in Escherichia coli. One clone, pDR-beta-1, obtained by hybrid selection, carries a 1070-base-pair insert comprising all of the coding region except the signal sequence and a substantial portion of the untranslated region. To identify pDR-beta-1, highly purified HLA-DR antigen beta chains derived from Raji cells were subjected to NH2-terminal amino acid sequence determination. This sequence displayed extensive homology with that deduced from the nucleotide sequence at the 5' end of the pDR-beta-1 coding region. Taken together, the amino acid and nucleotide sequences strongly argue in favor of Raji cells containing at least two beta-chain loci.

https://www.pnas.org/content/pnas/79/6/1703.full.pdf

Isolation and identification of a cDNA clone corresponding to an HLA-DR antigen beta chain.

The distribution of the cellular retinoic acid-binding protein (CRABP) in some rat tissues has been determined, and the protein has been localized by immunocytochemical techniques in sections from rat testis. In the testis CRABP was found in the seminiferous tubuli with Sertoli cells and the spermatogonia most intensely stained. All other cells of the germinal epithelium appeared largely devoid of CRABP. By use of an enzyme-linked immunosorbent assay CRABP was quantitatively estimated in several tissues and the highest levels were found in testis and eye. Comparisons of the tissue levels of CRABP and of the cellular retinol-binding protein (CRBP) did not reveal any apparent correlation.

Quantitation and tissue localization of the cellular retinoic acid-binding protein.

The embryonal carcinoma cell line F9 is known to differentiate when exposed to retinoic acid. We have examined the quantities of two intracellular retinoid-binding proteins in undifferentiated and differentiated F9 cells. The existence of a cell surface receptor that recognizes the plasma retinol-binding protein was also explored. It was shown that undifferentiated F9 cells contain low concentrations of the two retinoid-binding proteins. The cellular retinoic acid-binding protein was present in approximately 3-fold molar excess over the cellular retinol-binding protein. Upon culture in the presence of retinoic acid, F9 cells display elevated concentrations of both cellular retinol-binding protein and cellular retinoic acid-binding protein. Since the levels of β2-microglobulin, a marker of the differentiated state with no known involvement in the metabolism of vitamin A, increased in parallel with the retinoid-binding proteins, it seems unlikely that retinoic acid selectively increased the levels of the two retinoid-binding proteins. The differentiated, in contrast to the undifferentiated cells, can accumulate retinol from plasma retinol-binding protein and display a cell surface receptor for this protein. Despite the fact that retinoic acid-induced differentiation of F9 cells promotes increased levels of several proteins involved in the normal metabolism of vitamin A, no evidence was obtained to suggest that the cells were dependent on retinoids to maintain their differentiated state.

Johan Sundelin

Papers

The three-dimensional structure of retinol-binding protein.

Alpha chain of HLA-DR transplantation antigens is a member of the same protein superfamily as the immunoglobulins

Isolation and identification of a cDNA clone corresponding to an HLA-DR antigen beta chain.

Quantitation and tissue localization of the cellular retinoic acid-binding protein.

Increased levels of several retinoid binding proteins resulting from retinoic acid-induced differentiation of F9 cells.