Structure and Characterization of Phosphoglucomutase 5 from Atlantic and Baltic Herring—An Inactive Enzyme with Intact Substrate Binding

Phosphoglucomutase 5 (PGM5) in humans is known as a structural muscle protein without enzymatic activity, but detailed understanding of its function is lacking. PGM5 belongs to the alpha-D-phosphohexomutase family and is closely related to the enzymatically active metabolic enzyme PGM1. In the Atlantic herring, Clupea harengus, PGM5 is one of the genes strongly associated with ecological adaptation to the brackish Baltic Sea. We here present the first crystal structures of PGM5, from the Atlantic and Baltic herring, differing by a single substitution Ala330Val. The structure of PGM5 is overall highly similar to structures of PGM1. The structure of the Baltic herring PGM5 in complex with the substrate glucose-1-phosphate shows conserved substrate binding and active site compared to human PGM1, but both PGM5 variants lack phosphoglucomutase activity under the tested conditions. Structure comparison and sequence analysis of PGM5 and PGM1 from fish and mammals suggest that the lacking enzymatic activity of PGM5 is related to differences in active-site loops that are important for flipping of the reaction intermediate. The Ala330Val substitution does not alter structure or biophysical properties of PGM5 but, due to its surface-exposed location, could affect interactions with protein-binding partners.

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Influence of environmental conditions, population density, and prey type on the lipid content in Baltic herring (Clupea harengus membras) from the northern Baltic Sea

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2017-0504 ◽

2019 ◽

Vol 76 (4) ◽

pp. 576-585 ◽

Cited By ~ 2

Author(s):

Marjut Rajasilta ◽

Jari Hänninen ◽

Lea Laaksonen ◽

Päivi Laine ◽

Jukka-Pekka Suomela ◽

...

Keyword(s):

Climate Change ◽

Baltic Sea ◽

Lipid Content ◽

Sea Water ◽

Energy Content ◽

Global Climate ◽

Clupea Harengus ◽

Composition Analysis ◽

Baltic Herring ◽

The Baltic

Global climate change can affect the energy content of fish by altering their lipid physiology and consumption. We investigated the effects of different environmental stressors on the lipid content of the Baltic herring (Clupea harengus membras) from spawning ground samples that were collected annually in the northern Baltic Sea. During 1987–2014, the average lipid content of herring muscle decreased from 5%–6% (wet mass) to 1.5% (wet mass). Generalized linear mixed models indicated that sea water salinity and the size of the herring stock explained best the declining trend of lipid content. We estimated that the amount of the lipid storage incorporated in the spawning stock decreased by approximately 45% during the study, with respective energy content decreases. Fatty acid composition analysis revealed that herring lipids contained a high proportion of EPA (eicosapentaenoic acid; 20:5n-3) and DHA (docosahexaenoic acid; 22:6n-3), which likely originated from its main summertime prey, Limnocalanus macrurus. The results illustrate various climate change-induced processes leading to changes in the lipid content of the Baltic herring and, consequently, to changes in the energy flows of the northern Baltic ecosystem.

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Decreasing salinity improves the feeding conditions of the Baltic herring (Clupea harengus membras) during spring in the Bothnian Sea, northern Baltic

ICES Journal of Marine Science ◽

10.1093/icesjms/fsu047 ◽

2014 ◽

Vol 71 (5) ◽

pp. 1148-1152 ◽

Cited By ~ 16

Author(s):

M. Rajasilta ◽

J. Hänninen ◽

I. Vuorinen

Keyword(s):

Stomach Contents ◽

Clupea Harengus ◽

Trophic Levels ◽

Baltic Herring ◽

Important Link ◽

Limnocalanus Macrurus ◽

The Baltic ◽

Bothnian Sea

Abstract The stomach contents of the herring (Clupea harengus membras L.) from the Bothnian Sea, northern Baltic, were analysed during spring 2011 and 2013. The stomachs were full of Limnocalanus macrurus in May and June, and an improvement in the condition of herring was observed when fish started to feed on this prey. The analyses showed that Limnocalanus is currently an important link between lower trophic levels and Baltic herring in the Bothnian Sea.

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Peer Review #1 of "Thermal conditions and age structure determine the spawning regularities and condition of Baltic herring (Clupea harengus membras) in the NE of the Baltic Sea (v0.1)"

10.7287/peerj.7345v0.1/reviews/1 ◽

2019 ◽

Keyword(s):

Baltic Sea ◽

Peer Review ◽

Age Structure ◽

Thermal Conditions ◽

Clupea Harengus ◽

The Baltic Sea ◽

Baltic Herring ◽

The Baltic

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Discrimination of western Baltic spring-spawning and central Baltic herring (Clupea harengus L.) based on growth vs. natural tag information

ICES Journal of Marine Science ◽

10.1093/icesjms/fst064 ◽

2013 ◽

Vol 70 (6) ◽

pp. 1108-1117 ◽

Cited By ~ 10

Author(s):

Tomas Gröhsler ◽

Rainer Oeberst ◽

Matthias Schaber ◽

Niklas Larson ◽

Georgs Kornilovs

Keyword(s):

Age Groups ◽

Clupea Harengus ◽

Commercial Fisheries ◽

Survey Area ◽

Separation Function ◽

The Baltic Sea ◽

Quick Method ◽

Baltic Herring ◽

Abundance Indices ◽

The Baltic

Abstract Gröhsler, T., Oeberst, R., Schaber, M., Larson, N., and Kornilovs, G. 2013. Discrimination of western Baltic spring-spawning and central Baltic herring (Clupea harengus L.) based on growth vs. natural tag information. – ICES Journal of Marine Science, 70: 1108–1117. In the Baltic Sea, several stocks of herring (Clupea harengus L.) are surveyed and managed separately. For assessment purposes, a spatial stock separation based on ICES subdivisions is implemented. However, especially in the western Baltic, the distribution areas of two stocks, the western Baltic spring-spawning herring and the central Baltic herring, overlap. Results of regularly conducted surveys for assessment purposes indicated variable degrees of mixing of both stocks in the survey area, based on conspicuous differences in weights/lengths within certain age groups, especially in an area known for overlapping distribution of both stocks. At present, varying fractions of the central Baltic herring stock have not been taken into account during regular surveys conducted in the western Baltic, leading to possible undetected biases in assessment indices derived from these surveys. Additionally, methods otherwise applied for stock separation of Baltic herring so far are based on parameters that cannot readily be derived during regular surveys. In this paper, we present a simple and quick method to reliably allocate herring to either stock based on a separation function derived from survey-based length-at-age data, thus facilitating a more precise estimate of biomass and abundance indices from regular surveys and commercial fisheries.

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Purification and characterization of Ak.1 protease, a thermostable subtilisin with a disulphide bond in the substrate-binding cleft

Biochemical Journal ◽

10.1042/bj3500321 ◽

2000 ◽

Vol 350 (1) ◽

pp. 321-328 ◽

Cited By ~ 8

Author(s):

Helen S. TOOGOOD ◽

Clyde A. SMITH ◽

Edward N. BAKER ◽

Roy M. DANIEL

Keyword(s):

Active Site ◽

Substrate Binding ◽

Fold Increase ◽

Branched Chain Amino Acids ◽

Disulphide Bond ◽

Purification And Characterization ◽

Active Site Cleft ◽

Binding Cleft ◽

Branched Chain

Ak.1 protease, a thermostable subtilisin isolated originally from Bacillus st. Ak.1, was purified to homogeneity from the Escherichia coli clone PB5517. It is active against substrates containing neutral or hydrophobic branched-chain amino acids at the P1 site, such as valine, alanine or phenylalanine. The Km and kcat of the enzyme decrease with decreasing temperature, though not to the same degree with all substrates, suggesting that specificity changes with temperature. The protease is markedly stabilized by Ca2+ ions. At 70°C, a 10-fold increase in Ca2+ concentration increases the half-life by three orders of magnitude. Ak.1 protease is stabilized by Ca2+ to a greater extent than is thermitase. This may be due, in part, to the presence of an extra Ca2+-binding site in Ak.1 protease. Other metal ions, such as Sr2+, increase the thermostability of the enzyme, but to a significantly lower degree than does Ca2+. The structure of the protease showed the presence of a disulphide bond located within the active-site cleft. This bond influences both enzyme activity and thermostability. The disulphide bond appears to have a dual role: maintaining the integrity of the substrate-binding cleft and increasing the thermostability of the protease. The protease was originally investigated to determine its usefulness in the clean-up of DNA at high temperatures. However, it was found that this protease has a limited substrate specificity, so this application was not explored further.

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