The Ultra-Centrifuge and the Study of High-Molecular Compounds

Svedberg, The

doi:10.1038/1391051a0

Cited by 118 publications

(37 citation statements)

References 38 publications

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“…The oscillating protein-size distributions are found to be characteristic of all species and of all protein types and families (Berman et al 1994), confirming the 65-year-old general idea of T. Svedberg (Svedberg 1929). The above unit-size figures also confirm and extend earlier observations--namely, the first rough estimate of the unit size, 160 residues (Svedberg 1937), and the more recent figure of 110-160 residues for E. coli proteins (Savageau 1986). …”

Section: Protein Chain-length Distributionssupporting

confidence: 80%

Segmented structure of protein sequences and early evolution of genome by combinatorial fusion of DNA elements

Trifonov

1995

J Mol Evol

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A theory of an early stage of genome evolution by combinatorial fusion of circular DNA units is suggested, based on protein sequence "fossil" evidence. The evidence includes preference of protein sequence lengths for certain sizes--multiples of 123 aa for eukaryotes and multiples of 152 aa for prokaryotes. At the DNA level these sizes correspond to 350-450 base pairs--the known optimal range for DNA ring closure. The methionine residues repeatedly appear along the sequences with the same period of about 120 aa (in eukaryotes), presumably marking the sites of insertion of the early genes--rings of protein-coding DNA. No torsional constraint in this DNA results in very sharp estimate of the helical periodicity of the early DNA, indistinguishable from the experimental mean value for extant DNA. According to the combinatorial fusion theory, based on the above evidence, in the pregenomic, prerecombinational stage the genes and the noncoding sequences existed in form of autonomously replicating DNA rings of close to standard size, randomly segregating between dividing cells, like modern plasmids do. In the recombinational early genomic stage the rings started to fuse, forming larger DNA molecules consisting of several unit genes connected in various combinations and forming long protein-coding sequences (combinatorial fusion). This process, which involved, perhaps, noncoding sequences as well, eventually resulted in the formation of large genomes. The dispersed circular DNA--or, rather, evolutionarily advanced derivatives thereof--may still exist in the form of various mobile DNA elements.

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Section: Protein Chain-length Distributionssupporting

confidence: 80%

Segmented structure of protein sequences and early evolution of genome by combinatorial fusion of DNA elements

Trifonov

1995

J Mol Evol

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“…Let us take the usual 2/3 power relationship between sedimentation coefficient and molecular weight [8], and bovine serum albumin as standard (mol. wt 68 000, s 4.5).…”

Section: Resultsmentioning

confidence: 99%

Studies on the subunit composition of the M‐protein of sendai virus

Hewitt

1977

FEBS Letters

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“…Oligomeric Organization of the SBP-Examination of vicilinlike proteins using analytical ultracentrifugation or size-exclusion chromatography shows that these proteins are organized as stable homotrimers (43)(44)(45)(46)(47). In addition, the three-dimensional structure of phaseolin and canavalin shows that the trimer is composed of monomers arranged around a 3-fold axis of symmetry (7,8,10).…”

Section: ; Ref 4)mentioning

confidence: 99%

A Plasma Membrane Sucrose-binding Protein That Mediates Sucrose Uptake Shares Structural and Sequence Similarity with Seed Storage Proteins but Remains Functionally Distinct

Overvoorde¹,

Chao

Grimes

1997

Journal of Biological Chemistry

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Photoaffinity labeling of a soybean cotyledon membrane fraction identified a sucrose-binding protein (SBP). Subsequent studies have shown that the SBP is a unique plasma membrane protein that mediates the linear uptake of sucrose in the presence of up to 30 mM external sucrose when ectopically expressed in yeast. Analysis of the SBP-deduced amino acid sequence indicates it lacks sequence similarity with other known transport proteins. Data presented here, however, indicate that the SBP shares significant sequence and structural homology with the vicilin-like seed storage proteins that organize into homotrimers. These similarities include a repeated sequence that forms the basis of the reiterated domain structure characteristic of the vicilin-like protein family. In addition, analytical ultracentrifugation and nonreducing SDS-polyacrylamide gel electrophoresis demonstrate that the SBP appears to be organized into oligomeric complexes with a M r indicative of the existence of SBP homotrimers and homodimers. The structural similarity shared by the SBP and vicilin-like proteins provides a novel framework to explore the mechanistic basis of SBP-mediated sucrose uptake. Expression of the maize Glb protein (a vicilinlike protein closely related to the SBP) in yeast demonstrates that a closely related vicilin-like protein is unable to mediate sucrose uptake. Thus, despite sequence and structural similarities shared by the SBP and the vicilin-like protein family, the SBP is functionally divergent from other members of this group.The development of plant seeds involves the accumulation of carbon and nitrogen reserves in proteinaceous forms that can both withstand desiccation and be utilized as an energy source by the developing embryo during germination. In legume species, these predominant seed storage proteins are found enclosed in membrane-bound organelles known as protein bodies (1, 2). The globulin seed storage proteins generally fall into two main classes: legumin-like and vicilin-like proteins (1, 3-6). Under nonreducing conditions, the legumin-like proteins are found as hexameric complexes with sedimentation coefficients of 11 S. The subunits of these complexes are derived from a precursor peptide containing two domains: an N-terminal acidic ␣ chain and a C-terminal basic ␤ chain. Following proteolytic processing, these domains remain associated through interchain disulfide links. In contrast, the vicilin-like proteins are found as 7 S trimers under nonreducing conditions. The vicilinlike monomers are 50 -70-kDa polypeptides that undergo variable levels of post-translational proteolytic processing (1, 3).X-ray crystallography of the vicilin-like proteins phaseolin (7, 8) and canavalin (9, 10) has permitted the formation of a canonical three-dimensional model for vicilin-like molecules (8). Each monomer consists of two very similar structural domains reflecting a tandem duplication observed at the nucleotide and amino acid sequences. These tandem domains are composed of two structural elements: a compact eight-stra...

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The Ultra-Centrifuge and the Study of High-Molecular Compounds

Cited by 118 publications

References 38 publications

Segmented structure of protein sequences and early evolution of genome by combinatorial fusion of DNA elements

Segmented structure of protein sequences and early evolution of genome by combinatorial fusion of DNA elements

Studies on the subunit composition of the M‐protein of sendai virus

A Plasma Membrane Sucrose-binding Protein That Mediates Sucrose Uptake Shares Structural and Sequence Similarity with Seed Storage Proteins but Remains Functionally Distinct

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