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Comprehensive virology, 13. Structure and assembly: Primary, secondary, tertiary, and quaternary structures
Book 1065
Reviews
cal sketches of these interactions, little more information is available. In many cases our knowledge derives from studies of chemically or mutationally altered tRNAs in which the alterations themselves might have changed the tRNA conformation, distorting the ensuing scheme of interaction. In general, research of this kind is leading to a static, geometrical picture similar to that which crystallographers obtain. This approach is valuable, but more effort must be devoted to dynamic and thermodynamic studies if we are to have a clear understanding of the relation between a tRNA structure and its function during encounters with other molecules involved in protein synthesis. Some of the most elegant studies in tRNA research concern the mechanism of “proofreading” by synthetases during tRNA aminoacylation and by ribosomes during tRNA binding to coding triplets. The general outline of acceptable chemical theories explaining the discrimination processes seems clear. It is not yet apparent to what extent theories based solely on considerations of reaction rate kinetics add more to our understanding of error levels in translation. Nevertheless, our current knowledge of the processes of aminoacylation and translation, taken with the data on DNA replication accuracy, do give us an adequate understanding of how the exquisite precision of information transfer is maintained inside living cells. Although details of tRNA reactions on the ribosome are extremely difficult to study, the most fascinating results described in this book contribute to our emerging picture of ribosome function. The ribosome looms as a huge, multi-site enzyme with active sites formed by segments of strategically placed proteins and RNA molecules. It is even suggested that a tRNA molecule itself, when positioned in the peptidyl site, can contribute to the structure of the aminoacyl site. We see the ribosome as a versatile complex of molecules responding in terms of changing structure and function to the presence of charged or uncharged tRNA. I think we can expect to find more examples of “organelles” like the ribosome which are constructed to perform catalytic roles normally assigned to smaller molecules. The increasing availability of large amounts of pure materials resulting from cloning procedures will help provide the answers to some of the general questions described here. In-addition, a determined attack on the dynamic and thermodynamic parameters of tRNA actions and interactions seems&necessary for a significant advance in our understanding of this important class of macromolecules. It will not be easy. Sidney Altman Department of Biology Yale University New Haven, Connecticut
06520
Some of the News
Comprehensive Virology, 13. Structure and Assembly: Primary, Secondary, Tertiary, and Quaternary Structures. H. Fraenkel-Conrat and R. R. Wagner, eds. New York and London: Plenum Press. 652 pp. $39.50.
The nine chapters of this volume deal with procaryotic and eucaryotic viruses-their genes, gene products, membranes, particle composition and assembly. In a well organized chapter, W. Fiers describes the structure and function of RNA bacteriophage, emphasizing the structural aspects of the viral genome. Work performed in his laboratory that has led to the complete nucleotide sequence of MS2 is described in detail and accompanied by a beautiful color fold-out of the MS2 genome. I especially enjoyed reading the concluding portion of this chapter, which correlates the structure of the phage genome with its biological properties. Unfortunately the new and exciting finding of a fourth cistron in phage f2, coding for a lysis protein in an out-of-phase reading frame, is not mentioned, and thus a vital topic in the discussion of structure-function relationships in the RNA phage genome is missing. The structure of the RNA of eucaryotic viruses is discussed in a chapter written by H. Fraenkel-Conrat. He describes some of the techniques used to examine sequences at both termini of these RNAs, but neglects other analytical procedures also in use, such as the dihydroxylboryl-derivatized solid support system. Data that have appeared in press before mid-1978 are adequately covered, but the chapter is rapidly falling out of date. This is because the cloning methodology coupled with rapid DNA sequencing techniques have resulted in remarkable advances in our knowledge of RNA structure. Of course, as FraenkelConrat himself points out, classical RNA sequencing techniques will remain the tools for establishing natural RNA structure irrespective of what we learn from sequencing their cDNAs. G. M. Air took up quite a task in writing a chapter on DNA sequencing of viral genomes. After a brief description of the main DNA sequencing techniques now in use, she describes a wide variety of procaryotic and eucaryotic DNA viruses and lists the facts that were known about their genome structures as of about two years ago. With our knowledge about viral DNA sequences increasing about as fast as people can run their gels, it is virtually impossible to write a review on this topic which is anywhere near up to date. Substantial amounts of information have since been added
Cell 1066
in every major virus field. Air’s article therefore excels not in its immediacy but rather in its scope, providing a comprehensive view of the many systems now under study. Amino acid sequences of eucaryotic viral proteins have been compiled by S. Oroszlan and Ft. V. Gilden. Apart from a few plant virus systems, notably tobacco mosaic virus, where complete coat protein structures have been established, data derived from direct amino acid sequence analysis are scarce and largely restricted to the N or C terminal ends of the more readily available proteins. Of course, with so many nucleotide sequences now available, many peptide sequences can be deduced directly from the genomic sequence. Strangely enough, this fact is not mentioned here, although later pages of the book give examples. In their chapter on viral membranes, R. W. Compans and H.-D. Klenk write about the structure, composition and assembly of animal virus envelopes. The review reads like a catalog where overlapping features are listed separately for each virus system. Although an overview is attempted in the concluding pages, organization of all the facts in the form of a broad synopsis would clearly have been a better choice. As it stands, unique situations (for instance, the de novo membrane synthesis of vaccinia) are hard for the general reader to recognize, and structural aspects are not well contrasted with functional considerations. H. S. Ginsberg, himself one of the pioneers of adenovirus research, has compiled a very lucid chapter on the adenovirus structural proteins. A wealth of information is presented in well organized form. What makes the review especially enjoyable is the fact that the data are analyzed and weighed; the reader is able to appreciate the interest that this work has generated to the present day. In the chapter on adenovirus-SV40 hybrid viruses, C. T. Patch, A. S. Levine and A. M. Lewis, Jr. diligently review the sizable literature dealing with a most intriguing family of defective or nondefective recombinants. Unfortunately, the rapidity with which this area has progressed again leaves this report a little out of date. For example, the excitement of the splicing story which unfolded in the adenovirus field three years ago does not come to life in these pages. Furthermore, the authors leave it to the reader to find out for himself through assimilating the data why these hybrid viruses are so important for the elucidation of both SV40 and adenovirus gene functions. Nevertheless, this chapter is well organized and informative in providing a historical perspective. F. A. Eiserling (chapter 8) and W. B. Wood and J. King (chapter 9) deal with structure and assembly of the bacteriophages T4, h, P22, T7 and $29 in the two concluding chapters of this volume. Both the importance and the immediacy of these studies are well reflected in the reviews. Particularly noteworthy for
their vividness and clarity are the figures of phage morphology in Eiserling’s chapter. What is lacking is a good synopsis which would use both sets of data to formulate general pathways of phage head and tail assembly. In summary, this book contains a few good articles and a good deal of useful information. As is generally the case, those chapters which cover exciting areas in which research has been most rapid will seem dated. It stands to reason, however, that this book will find its way to the bookshelves of institutional libraries, where its value as a reference source will be undisputed. Valuable comments by my colleagues G. Khoury, G. Ravetch, M. Rosenberg, J. Seidman, N. Sternberg and D. Summers have been incorporated in this review. Heiner Westphal Laboratory of Molecular Genetics National Institute of Child Health and Human Development Bethesda, Maryland 20205
Tracking
the Radiolabel
Techniques of Autoradiography. vised. By A. W. Rogers. Amsterdam, New York, Oxford: land. 429 pp. 559.00.
3rd
edition,
re-
Elsevier/North-Hol-
Autoradiography-the detection by photographic means of the spatial distribution of a radioisotope-is one of the most versatile techniques of modern science. Its accidental use by Henri Becquerel in 1896 led to the discovery of radioactivity and ultimately to the understanding of nuclear instability which has made possible the fabrication of nuclear power plants and nuclear weapons as well as the synthesis of the radioisotopes so useful as tracers in biological studies. Most biologists who use autoradiography have sufficient knowledge of the procedural details to produce adequate autoradiograms for their own work, but they have not learned enough of the physics and chemistry of radioactive decay products and their interactions with photographic emulsions to maximize the sensitivity and information yield of their techniques. Many other biologists have not used autoradiography at all in situations where it would have been appropriate
Reviews
cal sketches of these interactions, little more information is available. In many cases our knowledge derives from studies of chemically or mutationally altered tRNAs in which the alterations themselves might have changed the tRNA conformation, distorting the ensuing scheme of interaction. In general, research of this kind is leading to a static, geometrical picture similar to that which crystallographers obtain. This approach is valuable, but more effort must be devoted to dynamic and thermodynamic studies if we are to have a clear understanding of the relation between a tRNA structure and its function during encounters with other molecules involved in protein synthesis. Some of the most elegant studies in tRNA research concern the mechanism of “proofreading” by synthetases during tRNA aminoacylation and by ribosomes during tRNA binding to coding triplets. The general outline of acceptable chemical theories explaining the discrimination processes seems clear. It is not yet apparent to what extent theories based solely on considerations of reaction rate kinetics add more to our understanding of error levels in translation. Nevertheless, our current knowledge of the processes of aminoacylation and translation, taken with the data on DNA replication accuracy, do give us an adequate understanding of how the exquisite precision of information transfer is maintained inside living cells. Although details of tRNA reactions on the ribosome are extremely difficult to study, the most fascinating results described in this book contribute to our emerging picture of ribosome function. The ribosome looms as a huge, multi-site enzyme with active sites formed by segments of strategically placed proteins and RNA molecules. It is even suggested that a tRNA molecule itself, when positioned in the peptidyl site, can contribute to the structure of the aminoacyl site. We see the ribosome as a versatile complex of molecules responding in terms of changing structure and function to the presence of charged or uncharged tRNA. I think we can expect to find more examples of “organelles” like the ribosome which are constructed to perform catalytic roles normally assigned to smaller molecules. The increasing availability of large amounts of pure materials resulting from cloning procedures will help provide the answers to some of the general questions described here. In-addition, a determined attack on the dynamic and thermodynamic parameters of tRNA actions and interactions seems&necessary for a significant advance in our understanding of this important class of macromolecules. It will not be easy. Sidney Altman Department of Biology Yale University New Haven, Connecticut
06520
Some of the News
Comprehensive Virology, 13. Structure and Assembly: Primary, Secondary, Tertiary, and Quaternary Structures. H. Fraenkel-Conrat and R. R. Wagner, eds. New York and London: Plenum Press. 652 pp. $39.50.
The nine chapters of this volume deal with procaryotic and eucaryotic viruses-their genes, gene products, membranes, particle composition and assembly. In a well organized chapter, W. Fiers describes the structure and function of RNA bacteriophage, emphasizing the structural aspects of the viral genome. Work performed in his laboratory that has led to the complete nucleotide sequence of MS2 is described in detail and accompanied by a beautiful color fold-out of the MS2 genome. I especially enjoyed reading the concluding portion of this chapter, which correlates the structure of the phage genome with its biological properties. Unfortunately the new and exciting finding of a fourth cistron in phage f2, coding for a lysis protein in an out-of-phase reading frame, is not mentioned, and thus a vital topic in the discussion of structure-function relationships in the RNA phage genome is missing. The structure of the RNA of eucaryotic viruses is discussed in a chapter written by H. Fraenkel-Conrat. He describes some of the techniques used to examine sequences at both termini of these RNAs, but neglects other analytical procedures also in use, such as the dihydroxylboryl-derivatized solid support system. Data that have appeared in press before mid-1978 are adequately covered, but the chapter is rapidly falling out of date. This is because the cloning methodology coupled with rapid DNA sequencing techniques have resulted in remarkable advances in our knowledge of RNA structure. Of course, as FraenkelConrat himself points out, classical RNA sequencing techniques will remain the tools for establishing natural RNA structure irrespective of what we learn from sequencing their cDNAs. G. M. Air took up quite a task in writing a chapter on DNA sequencing of viral genomes. After a brief description of the main DNA sequencing techniques now in use, she describes a wide variety of procaryotic and eucaryotic DNA viruses and lists the facts that were known about their genome structures as of about two years ago. With our knowledge about viral DNA sequences increasing about as fast as people can run their gels, it is virtually impossible to write a review on this topic which is anywhere near up to date. Substantial amounts of information have since been added
Cell 1066
in every major virus field. Air’s article therefore excels not in its immediacy but rather in its scope, providing a comprehensive view of the many systems now under study. Amino acid sequences of eucaryotic viral proteins have been compiled by S. Oroszlan and Ft. V. Gilden. Apart from a few plant virus systems, notably tobacco mosaic virus, where complete coat protein structures have been established, data derived from direct amino acid sequence analysis are scarce and largely restricted to the N or C terminal ends of the more readily available proteins. Of course, with so many nucleotide sequences now available, many peptide sequences can be deduced directly from the genomic sequence. Strangely enough, this fact is not mentioned here, although later pages of the book give examples. In their chapter on viral membranes, R. W. Compans and H.-D. Klenk write about the structure, composition and assembly of animal virus envelopes. The review reads like a catalog where overlapping features are listed separately for each virus system. Although an overview is attempted in the concluding pages, organization of all the facts in the form of a broad synopsis would clearly have been a better choice. As it stands, unique situations (for instance, the de novo membrane synthesis of vaccinia) are hard for the general reader to recognize, and structural aspects are not well contrasted with functional considerations. H. S. Ginsberg, himself one of the pioneers of adenovirus research, has compiled a very lucid chapter on the adenovirus structural proteins. A wealth of information is presented in well organized form. What makes the review especially enjoyable is the fact that the data are analyzed and weighed; the reader is able to appreciate the interest that this work has generated to the present day. In the chapter on adenovirus-SV40 hybrid viruses, C. T. Patch, A. S. Levine and A. M. Lewis, Jr. diligently review the sizable literature dealing with a most intriguing family of defective or nondefective recombinants. Unfortunately, the rapidity with which this area has progressed again leaves this report a little out of date. For example, the excitement of the splicing story which unfolded in the adenovirus field three years ago does not come to life in these pages. Furthermore, the authors leave it to the reader to find out for himself through assimilating the data why these hybrid viruses are so important for the elucidation of both SV40 and adenovirus gene functions. Nevertheless, this chapter is well organized and informative in providing a historical perspective. F. A. Eiserling (chapter 8) and W. B. Wood and J. King (chapter 9) deal with structure and assembly of the bacteriophages T4, h, P22, T7 and $29 in the two concluding chapters of this volume. Both the importance and the immediacy of these studies are well reflected in the reviews. Particularly noteworthy for
their vividness and clarity are the figures of phage morphology in Eiserling’s chapter. What is lacking is a good synopsis which would use both sets of data to formulate general pathways of phage head and tail assembly. In summary, this book contains a few good articles and a good deal of useful information. As is generally the case, those chapters which cover exciting areas in which research has been most rapid will seem dated. It stands to reason, however, that this book will find its way to the bookshelves of institutional libraries, where its value as a reference source will be undisputed. Valuable comments by my colleagues G. Khoury, G. Ravetch, M. Rosenberg, J. Seidman, N. Sternberg and D. Summers have been incorporated in this review. Heiner Westphal Laboratory of Molecular Genetics National Institute of Child Health and Human Development Bethesda, Maryland 20205
Tracking
the Radiolabel
Techniques of Autoradiography. vised. By A. W. Rogers. Amsterdam, New York, Oxford: land. 429 pp. 559.00.
3rd
edition,
re-
Elsevier/North-Hol-
Autoradiography-the detection by photographic means of the spatial distribution of a radioisotope-is one of the most versatile techniques of modern science. Its accidental use by Henri Becquerel in 1896 led to the discovery of radioactivity and ultimately to the understanding of nuclear instability which has made possible the fabrication of nuclear power plants and nuclear weapons as well as the synthesis of the radioisotopes so useful as tracers in biological studies. Most biologists who use autoradiography have sufficient knowledge of the procedural details to produce adequate autoradiograms for their own work, but they have not learned enough of the physics and chemistry of radioactive decay products and their interactions with photographic emulsions to maximize the sensitivity and information yield of their techniques. Many other biologists have not used autoradiography at all in situations where it would have been appropriate