title: A new allele of γ-kafirin gene coding for a protein with high lysine content in Mexican white sorghum germplasm.
abstract: BACKGROUND
  Low protein digestibility and lysine content of white sorghum grain limit its use as a foodstuff. The increase in γ-kafirin cross-linking, has an important role in the reduction of protein digestibility. The objective of this study was to characterize the γ-kafirin gene in 12 Mexican tannin-free white sorghum genotypes and its relationship with protein digestibility and lysine content.
  
  
  RESULTS
  Two alleles of γ-kafirin gene were identified: alleles 1 and 7. The predicted amino acid sequence of allele 7 showed seven point mutations; six were silent, and one missense (C235G), causing the substitution P79A in the deduced amino acid sequence. In silico analysis showed that γ-kafirin codified by allele 1 has five α-helixes without disulfide bonds, while γ-kafirin coding by allele 7 has four α-helixes and three disulfide bonds. Genotypes with allele 7 had higher lysine content than those with allele 1, showing no differences in the kafirin electrophoretic profile, neither a correlation with the protein content nor the in vitro pepsin digestibility.
  
  
  CONCLUSIONS
  Mexican tannin-free white sorghum genotypes showed two γ-kafirin alleles, 1 and 7. Allele 7 was associated with higher lysine content; in silico analysis showed that the substitution of P79A in this allele could modify γ-kafirin secondary structure. © 2015 Society of Chemical Industry.
authors.affiliation: Centro Multidisciplinario de Estudios en Biotecnología-Facultad de Medicina Veterinaria y Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, C.P. 58893, Morelia, Michoacán, México.
authors.forename: Elizabeth
authors.identifier: http://orcid.org/0000-0001-8289-1879
authors.initials: E
authors.lastname: Chiquito-Almanza
authors.affiliation: Centro Multidisciplinario de Estudios en Biotecnología-Facultad de Medicina Veterinaria y Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, C.P. 58893, Morelia, Michoacán, México.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Ochoa-Zarzosa
authors.affiliation: Centro Multidisciplinario de Estudios en Biotecnología-Facultad de Medicina Veterinaria y Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, C.P. 58893, Morelia, Michoacán, México.
authors.forename: Joel E
authors.initials: JE
authors.lastname: López-Meza
authors.affiliation: Unidad de Biotecnología, Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias, Campo Experimental Bajío. C.P. 38110, Celaya, Guanajuato, México.
authors.forename: Víctor
authors.initials: V
authors.lastname: Pecina-Quintero
authors.affiliation: Programa de Biotecnología, Universidad de Guanajuato, Mutualismo #303, Col. La Suiza, C.P. 38060, Celaya, Guanajuato, México.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Nuñez-Colín
authors.affiliation: Unidad de Biotecnología, Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias, Campo Experimental Bajío. C.P. 38110, Celaya, Guanajuato, México.
authors.forename: José L
authors.initials: JL
authors.lastname: Anaya-López
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D004044:Dietary Proteins / Q000378:metabolism; D004063:Digestion; D004220:Disulfides / Q000737:chemistry; D005838:Genotype; D008239:Lysine / Q000032:analysis*; D008800:Mexico; D010434:Pepsin A / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000072756:Protein Conformation, alpha-Helical; D017433:Protein Structure, Secondary; D012639:Seeds / Q000737:chemistry*; D045868:Sorghum / Q000737:chemistry*
chemical_list: D004044:Dietary Proteins; D004220:Disulfides; D010940:Plant Proteins; C080615:kafirin protein, Sorghum bicolor; D010434:Pepsin A; D008239:Lysine
keywords: lysine content; protein digestibility; secondary structure, disulfide bonds; white sorghum; γ-kafirin