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Protein secondary structures (α-helix and β-sheet) at a cellular level and protein fractions in relation to rumen degradation behaviours of protein: a new approach

  • Peiqiang Yu (a1)


Studying the secondary structure of proteins leads to an understanding of the components that make up a whole protein, and such an understanding of the structure of the whole protein is often vital to understanding its digestive behaviour and nutritive value in animals. The main protein secondary structures are the α-helix and β-sheet. The percentage of these two structures in protein secondary structures influences protein nutritive value, quality and digestive behaviour. A high percentage of β-sheet structure may partly cause a low access to gastrointestinal digestive enzymes, which results in a low protein value. The objectives of the present study were to use advanced synchrotron-based Fourier transform IR (S-FTIR) microspectroscopy as a new approach to reveal the molecular chemistry of the protein secondary structures of feed tissues affected by heat-processing within intact tissue at a cellular level, and to quantify protein secondary structures using multicomponent peak modelling Gaussian and Lorentzian methods, in relation to protein digestive behaviours and nutritive value in the rumen, which was determined using the Cornell Net Carbohydrate Protein System. The synchrotron-based molecular chemistry research experiment was performed at the National Synchrotron Light Source at Brookhaven National Laboratory, US Department of Energy. The results showed that, with S-FTIR microspectroscopy, the molecular chemistry, ultrastructural chemical make-up and nutritive characteristics could be revealed at a high ultraspatial resolution (∼10 μm). S-FTIR microspectroscopy revealed that the secondary structure of protein differed between raw and roasted golden flaxseeds in terms of the percentages and ratio of α-helixes and β-sheets in the mid-IR range at the cellular level. By using multicomponent peak modelling, the results show that the roasting reduced (P<0·05) the percentage of α-helixes (from 47·1 % to 36·1 %: S-FTIR absorption intensity), increased the percentage of β-sheets (from 37·2 % to 49·8 %: S-FTIR absorption intensity) and reduced the α-helix to β-sheet ratio (from 0·3 to 0·7) in the golden flaxseeds, which indicated a negative effect of the roasting on protein values, utilisation and bioavailability. These results were proved by the Cornell Net Carbohydrate Protein System in situ animal trial, which also revealed that roasting increased the amount of protein bound to lignin, and well as of the Maillard reaction protein (both of which are poorly used by ruminants), and increased the level of indigestible and undegradable protein in ruminants. The present results demonstrate the potential of highly spatially resolved synchrotron-based infrared microspectroscopy to locate ‘pure’ protein in feed tissues, and reveal protein secondary structures and digestive behaviour, making a significant step forward in and an important contribution to protein nutritional research. Further study is needed to determine the sensitivities of protein secondary structures to various heat-processing conditions, and to quantify the relationship between protein secondary structures and the nutrient availability and digestive behaviour of various protein sources. Information from the present study arising from the synchrotron-based IR probing of the protein secondary structures of protein sources at the cellular level will be valuable as a guide to maintaining protein quality and predicting digestive behaviours.


Corresponding author

*Corresponding author: Dr Peiqiang Yu, fax 306 966 4151, email


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Association of Official Analytical Chemists (1990) Official Methods of Analysis, 15th edn. Arlington, VA: AOAC.
Budevska, BO (2002) In Handbook of Vibrational Spectroscopy, vol. 5. Applications of Vibrational Spectroscopy in Life, Pharmaceutical and Natural Sciences, pp. 37203732. (Chalmers, JM and Griffiths, PR, editors). New York: John Wiley and Sons, Inc.
Carey, FA (1996) Organic Chemistry, 3rd edn. New York: McGraw-Hill.
Chalupa, W & Sniffen, CJ (1994) Carbohydrate, protein and amino acid nutrition of lactating dairy cattle. In Recent Advances in Animal Nutrition, pp. 265275 (Garnsworty, PC & Wiseman, J, editors) Loughborough: Nottingham University Press.
Chandler, NJ (2003) Dairy Cattle – Feather meal: its nutritional value and use in dairy and beef rations. (November 2003)/
Chaudhry, AS & Webster, AJF (1993) The true digestibility and biological value for rats of undegraded dietary nitrogen in feeds for ruminant. Anim Feed Sci Technol 42, 209221.
Dumas, P (2003) Synchrotron IR microspectroscopy: a multidisciplinary analytical technique. Sixth Annual Synchrotron CLS Users’ Meeting and Associated Synchrotron Workshops – WinXAS and Infrared.University of Saskatchewan,Canada,13–15 November.
Dyson, HJ & Wright, PE (1990) Peptide conformation and protein folding. Curr Opin Struct Biol 3, 6065.
Elizalde, JC, Merchen, NR & Faulkner, DB (1999) Fractionation of fiber and crude protein in fresh forages during the spring growth. J Anim Sci 77, 476484.
Fraser, RDB, MacCrae, TP & Rogers, GE (1972) Keratins. Springheld, USA: Charles C Thomas.
Goelema, JO (1999) Processing of legume seeds: effect on digestive behaviours in dairy cows. PhD Thesis, Wageningen Agricultural University, The Netherlands.
Greg, K & Rogers, GE (1986) Feather keratin: composition, structure and biogenesis. In Biology of Integuments, vol. 2. Heidelberg: Springer Verlag.
Griffiths, PR & Pariente, G (1986) Trends in analytical chemistry. In Introduction to Spectral Deconvolution, vol. 5, pp. 209. Amsterdam, Netherlands: Elsevier.
Himmelsbach, DS, Khalili, S & Akin, DE (1998) FT-IR microspectroscopic imaging of flax ( Linum usitatissimum L.) stems. Cell Mol Biol 44, 99108.
Holman, Hoi-Ying N, Bjornstad, KA, McNamara, MP, Martin, MC, McKinney, WR & Blakely, EA (2002) Synchrotron infrared spectromicroscopy as a novel bioanalytical microprobe for individual living cells: cytotoxicity considerations. J Biomed Optics 7, 110.
Holum, JR (1982) Fundamentals of General, Organic, and Biological Chemistry, 2nd edn. New York: J Wiley & Sons.
Jackson, M & Mantsch, HH (2000) Infrared spectroscopy ex vivo tissue analysis. In Encyclopedia of Analytical Chemistry, pp. 120 (Meyers, L, ed.). Chichester: John Wiley and Sons Ltd.
Kauppinen, JK, Moffatt, DJ, Mantsch, HH & Cameron, DG (1981) Fourier selfdeconvolution: a method for resolving intrinsically overlapped bands. Appl Spectroscy 35, 271276.
Kemp, W (1991) Organic Spectroscopy, 3rd edn., New York: WH Freeman.
Licitra, G, Hernandez, TM & Van Soest, PJ (1996) Standardization of procedures for nitrogen fractionation of ruminant feeds. Anim Feed Sci Technol 57, 347358.
Mantsch, HH & Chapman, D (1996) Infrared Spectroscopy of Biomolecules. New York: John Wiley & Sons.
Marinkovic, NS, Huang, R, Bromberg, P et al. (2002) Center for Synchrotron Biosciences’ U2B beamline: an international resource for biological infrared spectroscopy. J Synchrotron Radiat 9, 189197.
Martin, MC (2002) Fourier-transform infrared spectroscopy. http://www.nsls.bnc-gov/newsroom/publications/otherpubs/imaging0502/workshopmillerhighres.pdf (accessed 7 Sep 2005).
Miller, LM (2000) The impact of infrared synchrotron radiation on biology: past, present, and future. Synchrotron RadiatNews 13, 3137.
Miller, LM (2002) Infrared microspectroscopy and imaging. gov/newsroom/publications/otherpubs/imaging0502/workshopmillerhighres.pdf(accessed7sep05)
National Research Council (1996) Nutrient Requirement of Beef Cattle, 7th edn. Washington, DC: National Academy Press.
National Research Council (2001) Nutrient Requirement of Dairy Cattle, 7th edn. Washington, DC: National Academy Press.
Rebolé, A, Treviño, J, Caballero, R & Alzueta, C (2001) Effect of maturity on the amino acid profiles of total and nitrogen fractions in common vetch forage. J Sci Food Agric 81, 455461.
SAS (1998) User's Guide: Statistics, 8th edn., Cary, NC: SAS Institute.
Seguchi, M, Takemoto, M, Mizutani, U, Ozawa, M, Nakamura, C & Matsumura, Y (2004) Effects of secondary structures of heated egg white protein on the binding between prime starch and tailings fractions in fresh wheat flour. Cereal Chem 81, 633636.
Sniffen, CJ, O'Connor, JD, Van Soest, PJ, Fox, DG & Russell, JB (1992) A net carbohydrate and protein system for evaluating cattle diets. II. Carbohydrate and protein availability. J Anim Sci 70, 35623577.
Soita, HW, Meier, JA, Fehr, M, Yu, P, Christensen, DA, McKinnon, JJ & Mustafa, AF (2003) Effects of flaxseed supplementation on milk production, milk fatty acid composition and nutrient utilization by lactating dairy cows. Arch Anim Nutr 57, 107116.
Stewart, D, McDougall, GJ & Baty, A (1995) Fourier transform infrared microspectroscopy of anatomically different cells of falx ( Linum usitatissimum ) stems during development. J Agric Food Chem 43, 18531858.
Van der Poel, AFB, Blonk, J, Van Zuilichem, DJ & Van Oort, MG (1990) Thermal inactivation of lectins and trypsin inhibitor activity during steam processing of dry beans ( Phaseolus vulgaris ) and effects on protein quality. J Sci Food Agric 53, 215228.
Van Soest, PJ, Robertson, JB & Lewis, BA (1991) Symposium: Carbohydrate methodology, metabolism and nutritional implications in dairy cattle. Methods for dietary fiber, neutral detergent fiber and non-starch polysaccharides in relation to animal nutrition. J Dairy Sci 74, 35833597.
Ward Lundgren, HP (1954) Formation, composition and properties of keratins. Adv Protein Chem 9, 244297.
Weiss, WP, Conrad, HR & Pierre, NS (1992) A theoretically based model for predicting total digestible nutrient values of forages and concentrates. Anim Feed Sci Technol 39, 95110.
Wetzel, DL (2001) When molecular causes of wheat quality are known, molecular methods will supercede traditional methods. Proceedings of the Second International Wheat Quality Conference, Manhattan, Kansas, USA, May. 2001.
Wetzel, DL, Eilert, AJ, Pietrzak, LN, Miller, SS & Sweat, JA (1998) Ultraspatially resolved synchrotron infrared microspectroscopy of plant tissue in situ. Cell Mol Biol 44, 145167.
Wetzel, DL, Srivarin, P & Finney, JR (2003) Revealing protein infrared spectral detail in a heterogeneous matrix dominated by starch. Vib Spectrosc 31, 109114.
Yu, P (2004) Application of advanced synchrotron-based Fourier transform infrared microspectroscopy (SR-FTIR) to animal nutrition and feed science: a novel approach. Br J Nutr 92, 869885.
Yu, P, Goelema, JO, Leury, BJ, Tamminga, S & Egan, AR (2002) An analysis of the nutritive value of heat processed legume seeds for animal production using the DVE/OEB model: a review [Scientific review article]. Anim Feed Sci Technol 99, 141176.
Yu, P, McKinnon, JJ, Christensen, CR, & Christensen, DA (2003. a ) Mapping plant composition with synchrotron infrared microspectroscopy and relation to animal nutrient utilization [Invited article and conference speech]. Proceedings of the Canadian Society of Animal Science Conference, University of Saskatchewan, Saskatoon, Canada, 10–13 June.
Yu, P, McKinnon, JJ, Christensen, CR, Christensen, DA, Marinkovic, NS & Miller, LM (2003b) Chemical imaging of micro-structures of plant tissues within cellular dimension using synchrotron infrared microspectroscopy. J Agric Food Chem 51, 60626067.
Yu, P, McKinnon, JJ, Christensen, CR & Christensen, DA (2004a) Using synchrotron-based FTIR microspectroscopy to reveal chemical features of feather protein secondary structure: comparison with other feed protein sources. J Agric Food Chem 52, 73537361.
Yu, P, Tamminga, S, Egan, AR & Christensen, DA (2004b) Probing equivocal effects of heat processing of legume seeds on performance of ruminants – a review [Scientific review article]. Asian Austr J Anim Sci 17, 869876.
Yu, P, Christensen, DA, Christensen, CR, Drew, MD, Rossnagel, BG & McKinnon, JJ (2004c) Use of synchrotron FTIR microspectroscopy to identify chemical differences in barley endosperm tissue in relation to rumen degradation characteristics. Can J Anim Sci 84, 523527.
Yu, P, McKinnon, JJ, Christensen, DA & Christensen, CR (2004d) Applications of synchrotron technology (SR–FTIR) to feed analysis and utilization: a novel approach [Conference article]. Proceedings of the 25th Western Nutrition Conference, Nutrient Requirement and Ingredient Evaluation in the 21st Century.Saskatoon, Canada,28–30 September.
Yu, P, McKinnon, JJ, Christensen, CR & Christensen, DA (2004e) Using synchrotron transmission FTIR microspectroscopy as a rapid, direct and non-destructive analytical technique to reveal molecular microstructural-chemical features within tissue in grain barley. J Agric Food Chem 52, 14841494.
Yu, P, McKinnon, JJ, Christensen, CR & Christensen, DA (2004f) Imaging molecular chemistry of Pioneer corn. J Agric Food Chem 52, 73457352.
Yu, P, Christensen, DA, McKinnon, JJ & Soita, HW (2004g) Using chemical and biological approaches to predict energy values of selected forages affected by variety and maturity stage. Asian Austr J Anim Sci 17, 228236.
Yu, P (2005 a ) Using synchrotron infrared microspectroscopy to reveal microstructural-chemical features of feed/food/plant tissues at a cellular and subcellular level [Invited conference article and speech]. 96th American Oil Chemists Society Annual Conference and Expo,Salt Lake City, Utah, USA,1–4 May.
Yu, P (2005b) Application of cluster analysis (CLA) in feed chemical imaging to accurately reveal structural-chemical features of feeds within cellular dimension. J Agric Food Chem 53, 28722880.
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British Journal of Nutrition
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