Canine Plasminogen: Spectral Responses to Changes in 6-Aminohexanoate and Temperature

We studied the near UV absorption spectrum of canine plasminogen. There are 19 tryptophans, 19 phenylalanines and 34 tyrosines in the protein. 4th derivative spectra optimized for either tryptophan or tyrosine give a measure of the polarity of the environments of these two aromatic amino acids. Plasminogen at temperatures between 0°C and 37°C exists as a mixture of four conformations: closed-relaxed, open-relaxed, closed-compact, and open-compact. The closed to open transition is driven by addition of ligand to a site on the protein. The relaxed to compact transition is driven by increasing temperature from 0°C to above 15-20°C. When the conformation of plasminogen is mainly closed-relaxed, the 4th derivative spectra suggest that the average tryptophan environment is similar to a solution of 20% methanol at the same temperature. Under the same conditions, 4th derivative spectra suggest that the average tyrosine environment is similar to water. These apparent polarities change as the plasminogen is forced to assume the other conformations. We try to rationalize the information based on the known portions of the plasminogen structure.

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Directed exospermia: I. Biological modes of resistance to UV light are implied through absorption spectroscopy of DNA and potential UV screens

International Journal of Astrobiology ◽

10.1017/s1473550407003771 ◽

2007 ◽

Vol 6 (3) ◽

pp. 229-240 ◽

Cited By ~ 10

Author(s):

Andreja Zalar ◽

David Tepfer ◽

Søren V. Hoffmann ◽

John M. Kenney ◽

Sydney Leach

Keyword(s):

Amino Acids ◽

Absorption Spectrum ◽

Uv Light ◽

Life Forms ◽

Uv Absorption ◽

Dna Protection ◽

Current Role ◽

Terrestrial Life ◽

Selection Of ◽

Uv Absorption Spectrum

AbstractPanspermia, the dissemination of life through space, would require resistance to the conditions found in space, including UV light. All known life forms depend on DNA to store information. In an effort to understand the liabilities of DNA to UV light and modes of DNA protection in terrestrial life forms, we established UV–VUV (125–340 nm) absorption spectra for dry DNA and its polymerized components and mononucleotides, as well as for a selection of potential UV screens ubiquitous in all organisms, including proteins, selected amino acids and amines (polyamines and tyramine). Montmorillonite clay was included as a potential abiotic UV screen. Among the potential screens tested, adenosine triphosphate (ATP) appeared to be particularly attractive, because its UV absorption spectrum was similar to that of DNA. We suggest that the use of ATP in UV protection could have pre-dated its current role in energy transfer. Spectroscopy also showed that UV absorption varied according to nucleotide content, suggesting that base pair usage could be a factor in adaptation to given UV environments and the availability of UV screens.

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NonO, a non-POU-domain-containing, octamer-binding protein, is the mammalian homolog of Drosophila nonAdiss

Molecular and Cellular Biology ◽

10.1128/mcb.13.9.5593-5603.1993 ◽

1993 ◽

Vol 13 (9) ◽

pp. 5593-5603

Author(s):

Y S Yang ◽

J H Hanke ◽

L Carayannopoulos ◽

C M Craft ◽

J D Capra ◽

...

Keyword(s):

Amino Acids ◽

Dna Binding ◽

Protein Binding ◽

Aromatic Amino Acids ◽

Courtship Song ◽

Dna Binding Domain ◽

Binding Motifs ◽

Dna And Rna ◽

Pou Domain ◽

A Site

We have cloned the ubiquitous form of an octamer-binding, 60-kDa protein (NonO) that appears to be the mammalian equivalent of the Drosophila visual and courtship song behavior protein, no-on-transient A/dissonance (nonAdiss). A region unprecedently rich in aromatic amino acids containing two ribonuclear protein binding motifs is highly conserved between the two proteins. A ubiquitous form of NonO is present in all adult tissues, whereas lymphocytes and retina express unique forms of NonO mRNA. The ubiquitous form contains a potential helix-turn-helix motif followed by a highly charged region but differs from prototypic octamer-binding factors by lacking the POU DNA-binding domain. In addition to its conventional octamer duplex-binding, NonO binds single-stranded DNA and RNA at a site independent of the duplex site.

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