Refined structure of baboon α-lactalbumin at 1.7 Å resolution

Acharya, K. Ravi; Stuart, David I.; Walker, Nigel; Lewis, Mitchell; Phillips, David

doi:10.1016/0022-2836(89)90091-0

Cited by 316 publications

(233 citation statements)

References 101 publications

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“…Furthermore, the presence of fifteen aromatic residues almost evenly distributed in the sequence makes the use of these residues as probes of the folding of the entire protein relatively easy. In the native state, some of the aromatic residues are spatially close and form two aromatic clusters (Acharya et al, 1989;Alexandrescu et al, 1992). The first comprises Phe31, His32, Tyr36 and Trpll8 while the second contains Trp26, Phe53, Trp60, Tyrl03 and Trpl04.…”

Section: Discussionmentioning

confidence: 99%

Probing Protein Structure by Solvent Perturbation of NMR Spectra

Improta

Molinari

Pastore

et al. 1995

European Journal of Biochemistry

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We have characterized the high-temperature molten globule state of bovine a-lactalbumin by a combined use of photochemically induced dynamic nuclear polarization and nitroxide surface perturbation. Both techniques are extremely well suited to follow the progressive increase of exposed surfaces in the native state and the appearance of partially or completely unfolded species. Our results suggest that the molten globule state obtained at high temperature and pH 7, and the state obtained at pH 2 are not only thermodynamically but also structurally very similar.

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Section: Discussionmentioning

confidence: 99%

Probing Protein Structure by Solvent Perturbation of NMR Spectra

Improta

Molinari

Pastore

et al. 1995

European Journal of Biochemistry

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“…In addition to the mutant structures discussed above, they are found in guinea fowl [Thr 911 (Lescar et al, 1994) and human [Ala 921 (Blake et al, 1983) lysozymes, as well as in a-lactalbumins [Asp 881 (Acharya et al, 1989). (The residues in brackets are equivalent to Ser 91 in chicken.)…”

Section: Conserved Buried Water Molecules In the Lysozyme Corementioning

confidence: 97%

“…(The residues in brackets are equivalent to Ser 91 in chicken.) a-Lactalbumin is evolutionarily related to chicken lysozyme by the 35% amino acid sequence identity and the structural similarity of the two proteins (Acharya et al, 1989). The invariant carboxylate group of Asp 88 in the a-lactalbumins serves as a coordination site for calcium.…”

Section: Conserved Buried Water Molecules In the Lysozyme Corementioning

confidence: 99%

Thermal stability determinants of chicken egg‐white lysozyme core mutants: Hydrophobicity, packing volume, and conserved buried water molecules

1995

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A series of 24 mutants was made in the buried core of chicken lysozyme at positions 40, 5 5 , and 91. The midpoint temperature of thermal denaturation transition (T,) values of these core constructs range from 60.9 to 77.3 "C, extending an earlier, more limited investigation on thermostability. The T,,, values of variants containing conservative replacements for the wild type (WT) (Thr 40-Ile 55-Ser 91) triplet are linearly correlated with hydrophobicity (r = 0.81) and, to a lesser degree, with combined side-chain volume (r = 0.75). The X-ray structures of the S91A (1.9A) and 155L/S91T/DlOlS (1.7 A) mutants are presented. The former amino acid change is found in duck and mammalian lysozymes, and the latter contains the most thermostable core triplet. A network of four conserved, buried water molecules is associated with the core. It is postulated that these water molecules significantly influence the mutational tolerance at the individual triplet positions. The pH dependence of T, for the S91D mutant was compared with that of WT enzyme. The pK, of S91D is 1.2 units higher in the native than in the denatured state, corresponding to AAG298 = 1.7 kcal/mol. This is a low value for charge burial and likely reflects the moderating influence of the buried water molecules or a conformational change. Thermal and chemical denaturation and far UV CD spectroscopy were used to characterize the in vitro properties of I55T. This variant, which buries a hydroxyl group, has similar properties to those of the human amyloidogenic variant I56T.

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“…The native protein is one of two components in the lactose synthase complex which catalyses the final step in lactose biosynthesis in the lactating mammary gland [5]. α-Lactalbumin has a molecular size of 14 kDa and consists of 122-123 amino acids, divided into two domains [6]. The large α -helical domain contains three major α-helices (amino acids 5-11, 23-34, 86-98) and two short 3 10 -helices (amino acids [18][19][20][115][116][117][118].…”

Section: Introductionmentioning

confidence: 99%

α-Lactalbumin species variation, HAMLET formation, and tumor cell death

Pettersson

Mossberg

Svanborg

2006

Biochemical and Biophysical Research Communications

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HAMLET (human α-lactalbumin made lethal to tumor cells) is a tumoricidal complex of apo α-lactalbumin and oleic acid, formed in casein after low pH treatment of human milk. This study examined if HAMLET-like complexes are present in casein from different species and if isolated α-lactalbumin from those species can form such complexes with oleic acid. Casein from human, bovine, equine and porcine milk were separated by ion exchange chromatography and active complexes were only found in human casein. This was not explained by α-lactalbumin sequence variation, as purified bovine, equine, porcine and caprine α-lactalbumins formed complexes with oleic acid with biological activity similar to HAMLET. We conclude that structural variation of α-lactalbumins does not preclude the formation of HAMLET-like complexes and that natural HAMLET formation in casein was unique to human milk, which also showed the highest oleic acid content.

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Refined structure of baboon α-lactalbumin at 1.7 Å resolution

Cited by 316 publications

References 101 publications

Probing Protein Structure by Solvent Perturbation of NMR Spectra

Probing Protein Structure by Solvent Perturbation of NMR Spectra

Thermal stability determinants of chicken egg‐white lysozyme core mutants: Hydrophobicity, packing volume, and conserved buried water molecules

α-Lactalbumin species variation, HAMLET formation, and tumor cell death

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