Biomedical subjects

K Harata

Publications and source records attributed to K Harata.

At least 37 records · Page 2Linked to original sources

PubMed1998

Full-matrix least-squares refinement of lysozymes and analysis of anisotropic thermal motion.

Crystal structures of turkey egg lysozyme (TEL) and human lysozyme (HL) were refined by full-matrix least-squares method using anisotropic temperature factors. The refinement converged at the conventional R-values of 0.104 (TEL) and 0.115 (HL) for reflections with Fo > 0 to the resolution of 1.12 A and 1.15 A, respectively. The estimated r.m.s. coordinate errors for protein atoms were 0.031 A (TEL) and 0.034 A (HL). The introduction of anisotropic temperature factors markedly reduced the R-value but did not significantly affect the main chain coordinates. The degree of anisotropy of atomic thermal motion has strong positive correlation with the square of distance from the molecular centroid. The ratio of the radial component of thermal ellipsoid to the r.m.s. magnitude of three principal components has negative correlation with the distance from the molecular centroid, suggesting the domination of libration rather than breathing motion. The TLS model was applied to elucidate the characteristics of the rigid-body motion. The TLS tensors were determined by the least-squares fit to observed temperature factors. The profile of the magnitude of reproduced temperature factors by the TLS method well fitted to that of observed B(eqv). However, considerable disagreement was observed in the shape and orientation of thermal ellipsoid for atoms with large temperature factors, indicating the large contribution of local motion. The upper estimate of the external motion, 67% (TEL) and 61% (HL) of B(eqv), was deduced from the plot of the magnitude of TLS tensors determined for main chain atoms which were grouped into shells according to the distance from the center of libration. In the external motion, the translational portion is predominant and the contribution of libration and screw motion is relatively small. The internal motion, estimated by subtracting the upper estimate of the external motion from the observed temperature factor, is very similar between TEL and HL in spite of the difference in 54 of 130 amino acid residues and in crystal packing, being suggested to reflect the intrinsic internal motion of chicken-type lysozymes.

Animals↗

PubMed1997

X-ray structure of turkey-egg lysozyme complex with tri-N-acetylchitotriose. Lack of binding ability at subsite A.

The turkey-egg lysozyme (TEL) complex with tri-N-acetylchitotriose [(GlcNac)3] was co-crystallized from 1.5% TEL and 2 mM (GlcNac)3 at pH 4.2. The crystal structure was determined by molecular replacement and refined to an R value of 0.182 using 10-1.77 A data. The (GlcNac)3 molecule occupies the subsites A, B and C. At the subsites B and C, the sugar residues are bound in a similar manner to that found in the hen-egg lysozyme (HEL) complex. In contrast, the GlcNac residue at the subsite A is exposed to bulk solvent and has no contact with the protein molecule because the active residue Asp101 in HEL is replaced by Gly in TEL. A sulfate ion is bound in the vicinity of subsite B and forms hydrogen bonds with the sugar residue and the guanidino group of Arg61, assisting the binding of the sugar residue to subsite B. The active-site cleft of TEL is narrower than that of native TEL, thus attaining the best fit of the (GlcNac)3 molecule. The lack of binding ability of subsite A is discussed in relation to the catalytic properties of TEL. The result suggests that the cleavage pattern of oligosaccharide substrates in the catalytic reaction is regulated by the protein-sugar interaction at subsite A.

Journal Article↗

PubMed1997

Importance of van der Waals contact between Glu 35 and Trp 109 to the catalytic action of human lysozyme.

The importance of van der Waals contact between Glu 35 and Trp 109 to the active-site structure and the catalytic properties of human lysozyme (HL) has been investigated by site-directed mutagenesis. The X-ray analysis of mutant HLs revealed that both the replacement of Glu 35 by Asp or Ala, and the replacement of Trp 109 by Phe or Ala resulted in a significant but localized change in the active-site cleft geometry. A prominent movement of the backbone structure was detected in the region of residues 110 to 120 and in the region of residues 100 to 115 for the mutations concerning Glu 35 and Trp 109, respectively. Accompanied by the displacement of the main-chain atoms with a maximal deviation of C alpha atom position ranging from 0.7 A to 1.0 A, the mutant HLs showed a remarkable change in the catalytic properties against Micrococcus luteus cell substrate as compared with native HL. Although the replacement of Glu 35 by Ala completely abolished the lytic activity, HL-Asp 35 mutant retained a weak but a certain lytic activity, showing the possible involvement of the side-chain carboxylate group of Asp 35 in the catalytic action. The kinetic consequence derived from the replacement of Trp 109 by Phe or Ala together with the result of the structural change suggested that the structural detail of the cleft lobe composed of the residues 100 to 115 centered at Ala 108 was responsible for the turnover in the reaction of HL against the bacterial cell wall substrate. The results revealed that the van der Waals contact between Glu 35 and Trp 109 was an essential determinant in the catalytic action of HL.

Catalysis↗

PubMed1996

X-ray structure of cyclodextrin glucanotransferase from alkalophilic Bacillus sp. 1011. Comparison of two independent molecules at 1.8 A resolution.

Cyclodextrin glucanotransferase (CGTase) is an enzyme which produces cyclodextrins by the degradation of starch. The enzyme from alkalophilic Bacillus sp. 1011, consisting of 686 amino acid residues, was crystallized from the solution containing 20% PEG 3000 and 20% 2-propanol at pH 5.6 adjusted with citrate buffer. The space group was P1 and the unit cell contained two molecules (V(m) = 2.41 A(3) Da(-1)). The structure was solved by the molecular replacement method and refined to a conventional R value of 0.161 (R(free) = 0.211) for the reflections in the resolution range 1.8-10 A by energy minimization combined with simulated annealing. The molecule consists of five domains, designated A-E, and its backbone structure is similar to the structure of other bacterial CGTases. The molecule has two calcium binding sites where calcium ions are coordinated by seven ligands, forming a distorted pentagonal bipyramid. The two independent molecules are related by a pseudotwofold symmetry and are superimposed with an r.m.s. deviation value of 0.32 A for equivalent C(alpha) atoms. Comparison of these molecules indicated the relatively large mobility of domains C and E with respect to domain A. The active site is filled with water molecules forming a hydrogen-bond network with polar side-chain groups. Two water molecules commonly found in the active center of both molecules link to several catalytically important residues by hydrogen bonds and participate in maintaining a similar orientation of side chains in the two independent molecules.

Journal Article↗

PubMed1996

Origin of carbohydrate recognition specificity of human lysozyme revealed by affinity labeling.

In order to reveal the origin of carbohydrate recognition specificity of human lysozyme by clarifying the difference in the binding mode of ligands in the active site, the inactivation of human lysozyme by 2',3'-epoxypropyl beta-glycoside derivatives of the disaccharides, N,N'-diacetylchitobiose [GlcNAc-beta-(1-->4)-GlcNAc] and N-acetyllactosamine [Gal-beta-(1-->4)-GlcNAc], was investigated and the three-dimensional structures of the affinity-labeled enzymes were determined by X-ray crystallography at 1.7 A resolution. Under the conditions comprising 2.0 x 10(-3) M labeling reagent and 1.0 x 10(-5) M human lysozyme at pH 5.4, 37 degrees C, the reaction time required to reduce the lytic activity against Micrococcus luteus cells to 50% of its initial activity was lengthened by 3.7 times through the substitution of the nonreducing end sugar residue, GlcNAc to Gal. The refined structure of human lysozyme labeled by 2',3'-epoxypropyl beta-glycoside derivatives of N,N'-diacetylchitobiose (HL/NAG-NAG-EPO complex) indicated that the interaction mode of the N,N'-diacetylchitobiose moiety in substites B and C in this study was essentially the same as in the case of the complex of human lysozyme with the free ligand. On the other hand, the hydrogen-bonding pattern and the stacking interaction at subsite B were remarkably different between the HL/NAG-NAG-EPO complex and human lysozyme labeled by the 2',3'-epoxypropyl beta-glycoside of N-acetyllactosamine (HL/GAL-NAG-EPO complex). The reduced number of possible hydrogen bonds as well as the less favorable stacking between the side chain of Tyr63 in human lysozyme and the galactose residue in the HL/GAL-NAG-EPO complex reasonably explained the less efficient ability of the 2',3'-epoxypropyl beta-glycoside of N-acetyllactosamine as compared to that of N,N'-diacetylchitobiose as an affinity labeling reagent toward human lysozyme.

Affinity Labels↗

PubMed1996

Mutant Met121Ala of Pseudomonas aeruginosa azurin and its azide derivative: crystal structures and spectral properties.

The crystal structures of the azurin mutant Met121Ala and its azide derivative Met121Ala-azide from Pseudomonas aeruginosa have been determined. The final crystallographic R values are 21.3 and 19.4% for the two structures, respectively. In the Met121Ala mutant, the distance between the copper ion and His117 increases by 0.34 A compared with the wild-type structure. The removal of the methionine in the apical position induces a shortening of the distance from the copper ion to the carbonyl O atom of Gly45 from 2.97 to 2.74 A. In the Met121Ala-azide structure, the azide anion occupies the cavity created by replacing the Met121 side chain with the smaller methyl group of Ala. The azide anion binds with a terminal N atom to the copper ion at a distance of about 2.04 A. In addition, the copper ion has moved out of the trigonal plane by about 0.26 A towards the azide anion. Thus, the copper site in this structure has a distorted tetrahedral arrangement. The spectroscopic characteristics show, in addition, that the copper sites in the two structures are distinctively different. The Met121Ala mutant still maintains the properties of an ordinary type 1 copper site while the Met121Ala-azide derivative has an absorption maximum at about 409 nm and the copper hyperfine coupling has increased to a value intermediate between those of type 2 copper and the wild-type azurin.

Journal Article↗

PubMed1995

X-ray structure of wheat germ agglutinin isolectin 3.

Wheat germ agglutinin isolectin 3 (WGA3) was crystallized from 10 mM acetate buffer at pH 4.9 containing 6 mM CaCl(2) and 4%(v/v) ethanol. The crystal belongs to monoclinic space group P2(1) with unit-cell dimensions a = 44.86, b = 91.02, c = 44.86 A, and beta = 110.22 degrees. The asymmetric unit contains two molecules (V(m) = 2.51 A(3) Da(-1)). The crystal structure was solved by the molecular-replacement method and was refined by the simulated-annealing method. The conventional R value was 0.191 for 19713 reflections [|F(o)| > 3sigma(F)] in the resolution range 8-1.9 A. The r.m.s. deviations from the ideal bond distances and angles were 0.014 A, and 3.0 degrees, respectively, and the estimated coordinate error was 0.2-0.25 A. The two molecules in the asymmetric unit are related by the pseudo twofold symmetry and form a dimer structure. The backbone structures of the two subunits are nearly identical with the r.m.s. difference of 0.36 A for the superposition of equivalent C(alpha) atoms. The dimer structure is very similar to those of isolectins 1 and 2 with the r.m.s. difference of 0.35-0.39 A for the C(alpha) superposition. Since amino-acid residues which differ from those of isolectin 1 or 2 are not involved in the contact between the two subunits, the subunit-subunit interaction is not significantly affected by the replacement of these residues. As a result, the geometry of the sugar-binding sites which are located at the interface between the two subunit molecules is basically conserved among three isolectins.

Journal Article↗

PubMed1995

Site-directed mutagenesis and sugar-binding properties of the wheat germ agglutinin mutants Tyr73Phe and Phe116Tyr.

Wheat germ agglutinin is a dimeric lectin composed of two identical subunits. Each subunit consists of four homologous hevein-like domains of 42 or 43 amino acids each. Amino acid residues at the same position in each domain involved in sugar binding are thought to play a similar role in sugar binding. In order to clarify the role of the amino acid residue at domain position 30 of wheat germ agglutinin isolectin 2 (WGA2) in sugar binding, two WGA2 variants each containing a mutation, either Tyr73-->Phe (domain B) or Phe116-->Tyr (domain C), were produced. The binding activity for (GlcNAc)3 and the three-dimensional structure of these mutants were characterized by comparing with the properties of wild-type WGA2. Equilibrium dialysis experiments using (GlcNAc)3 indicated that the mutation Tyr73-->Phe reduced the overall sugar-binding activity at both pH 5.9 and pH 4.7. In addition, positive cooperativity toward (GlcNAc)3 binding was observed at pH 4.7. In contrast, the mutation of Phe116-->Tyr increased the overall sugar-binding activity at pH 5.9, but reduced this activity at pH 4.7 without changing the number of sugar-binding sites. Positive cooperativity was not observed at pH 5.9 or pH 4.7. X-ray crystallographic analysis of mutant WGA2 revealed that the mutation of Tyr73-->Phe caused a side chain movement of the Glu115 residue of the opposite subunit that formed a hydrogen bond with Tyr73 in wild-type WGA2. No changes were observed in the backbone structure and the disposition of the benzene ring of Phe73. The mutation Phe116-->Tyr caused the formation of a new hydrogen bond between Tyr116 and Glu72 of the opposite subunit. The changes in the sugar-binding properties in WGA2 mutants are discussed in relation to the structural change at the binding site.

Base Sequence↗

PubMed1995

X-ray structure of turkey egg lysozyme complex with di-N-acetyl-chitobiose. Recognition and binding of alpha-anomeric form.

The crystalline complex of turkey-egg lysozyme (TEL) with di-N-acetylchitobiose (NAG2) was prepared by a soaking method and the structure was determined by X-ray analysis at 1.55 A resolution. The structure was refined to an R value of 0.175 by simulated annealing and energy minimization. The alpha-anomer of NAG2 is located at subsite D with the orientation perpendicular to the direction of the active-site cleft. The anomeric residue is deeply inserted into the cleft and the O1-H hydroxyl group is hydrogen bonded to the carboxyl group of Glu35 which is a catalytic residue. The other sugar residue protrudes outside the cleft and is in van der Waals contact with the beta-sheet region comprising of residues 43-53. The binding of NAG2 makes the active-site cleft 0.3-0.5 A narrower and suppresses the thermal motion of two lobes constructing the cleft. The NAG2 molecule is bound in a manner not assumed in the catalytic action of the enzyme and the geometry of binding indicates that the alpha-anomer blocks the active center and acts only as an inhibitor.

Journal Article↗

PubMed1995

Regioselectivity of alkylation of cyclomaltoheptaose (beta-cyclodextrin) and synthesis of its mono-2-O-methyl, -ethyl, -allyl, and -propyl derivatives.

Mono-2-O-methyl-, -2-O-ethyl-, and -2-O-allyl-cyclomaltoheptaose were prepared by alkylations of cyclomaltoheptaose in dilute aqueous alkali, and mono-2-O-propylcyclomaltoheptaose was obtained by hydrogenation of the allyl derivative. All the 2-O-alkyl derivatives were less soluble in water than was cyclomaltoheptaose. All formed inclusion complexes with toluene in aqueous solution, but only the methyl ether was less soluble in the water-toluene system than in water. The solubilities of the other ethers in water were enhanced by the addition of toluene. Partial methylation of cyclomaltoheptase with 13C-enriched dimethyl sulfate in dilute aqueous alkali yielded mixtures of products. The substitution patterns were analyzed by GLC-MS of the alditol acetates, prepared by hydrolysis, reduction, and acetylation, and by 13C NMR after complete permethylation with nonenriched reagent. The results showed that methylation at O-2 is a predominant but not an exclusive reaction; as expected, the regioselectivity decreases with increasing degree of methylation.

Alkylation↗

PubMed1994

Alteration of the substrate specificity of human lysozyme by site-specific intermolecular cross-linking.

Human lysozyme dimers were prepared by the intermolecular cross-linking of the monomer that contained the mutation of either Arg41 to Cys or Ala73 to Cys with a divalent maleimide compound. Among the three kinds of possible dimers only R41C-R41C dimer, in which the two catalytic clefts can come close to each other due to the proximity of the conjugation site to the active sites, turned out to be 2.3 times more specific to a polymer substrate, ethylene glycol chitin, as compared to an oligomer substrate, PNP-(GlcNAc)5. The result indicates that it is possible to alter the substrate specificity of an enzyme by artificially controlling the orientation of the active sites.

Alanine↗

PubMed1994

X-ray structure of a monoclinic form of hen egg-white lysozyme crystallized at 313 K. Comparison of two independent molecules.

A monoclinic crystal of hen egg lysozyme (HEL, E.C. 3.2.1.17) was obtained at 313 K from a 10%(w/v) NaCl solution at pH 7.6 containing 5%(v/v) 1-propanol. Cell dimensions were a = 27.23, b = 63.66, c = 59.12 A and beta = 92.9 degrees, and the space group was P2(1). The unit cell contains four molecules (V(m) = 1.79 A(3) Da(-1)). The structure was solved by the isomorphous replacement method with anomalous scattering followed by phase improvement by the solvent-flattening method. The refinement of the structure was carried out by the simulated-annealing method. The conventional R value was 0.187 for 18 260 reflections [|F(o)| > 3sigma(F)] in the resolution range 10-1.72 A. The r.m.s. deviations from the ideal bond distances and angles were 0.015 A and 3.0 degrees, respectively. The two molecules in the asymmetric unit are related by a translation of half a lattice unit along the a and c axes. The r.m.s. difference of equivalent C(alpha) atoms between the two molecules was 0.64 A and the largest difference was 3.57 A for Gly71. A significant structural change was observed in the regions of residues 45-50, 65-73 and 100-104. The residues 45-50, which connect two beta-strands, are shifted parallel to the beta-sheet plane between the two molecules. The residues 100-104 belong to the substrate-binding site (subsite A) and the high flexibility of this region may be responsible for the binding of the substrate and the release of reaction products.

Journal Article↗

PubMed1994

Crystallization and preliminary X-ray studies of cyclodextrin glucanotransferase from alkalophilic Bacillus sp. 1011.

Large crystals of cyclodextrin glucanotransferase (CGTase) from alkalophilic Bacillus sp. 1011, a typical alkalophilic enzyme, have been obtained at room temperature using polyethylene glycol 3000 and 2-propanol as precipitant. They belong to the triclinic space group P1 with the following unit cell constants: a = 64.93 A, b = 74.45 A, c = 79.12 A, alpha = 85.2 degrees, beta = 105.0 degrees and gamma = 101.0 degrees. The crystallographic asymmetric unit seems to contain two molecules of CGTase, with crystal volume per protein mass (Vm) of 2.41 A3/Da and solvent content of 49% by volume. The crystals diffract to at least 2.0 A resolution and they are suitable for X-ray analysis.

Bacillus↗

PubMed1993

Role of Arg115 in the catalytic action of human lysozyme. X-ray structure of His115 and Glu115 mutants.

The structure of modified human lysozymes (HLs), in which Arg115 is replaced by His or Glu, has been investigated by X-ray analysis at 1.77 A resolution. The mutation of the 115th residue by His does not affect the backbone structure as indicated by a root-mean-square deviation (r.m.s.d) of 0.14 A for the superposition of equivalent C alpha atoms between His115 HL and wild-type HL. In contrast, the corresponding r.m.s.d. value for Glu115 HL is 0.38 A which is twice as large as the estimated co-ordinate error of 0.2 A. Movement of the backbone structure is observed in the region of residues 100 to 130, which give an r.m.s.d. value of 0.61 A and a maximum deviation of 1.46 A for Arg119. A significant movement is also observed in the region of residues 45 to 50, which are located at the opposite side of the region of residues 100 to 120 with respect to the active site cleft. As a result, the active site cleft of Glu115 HL is narrower than the cleft of His115 HL or wild-type HL. This structural change is considered to be responsible for the low catalytic activity of Glu115 HL and the change of the catalytic property found in the hydrolysis of oligosaccharides. The replacement of Arg115 by Glu changes the charge distribution in the molecule, and the change in the electrostatic field may affect polar interactions among residues. The side-chain group of His115 and Glu115 is almost parallel to the indole moiety of Trp34, but the carboxyl group of Glu115 is laterally shifted to avoid overlapping with the indole moiety. The carboxylate anion of Glu115, which does not favor the face-to-face contact with aromatic groups, may provide a driving force for the structural change. The prominent structural change caused by the single mutation suggests that Arg115 is a key residue in maintaining the structure of the active site cleft.

Arginine↗

PubMed1993

Crystal structure of 6-O-[(R)-2-hydroxypropyl]cyclomaltoheptaose and 6-O-[(S)-2-hydroxypropyl]cyclomaltoheptaose.

Crystal structures of 6-O-[(R)-2-hydroxypropyl]- and 6-O-[(S)-2-hydroxypropyl]-cyclomaltoheptaose were determined by X-ray analysis. In both structures, the 2-hydroxypropyl group is inserted into the macrocyclic cavity of the next molecule related by the two-fold screw axis, and a helically extended polymeric structure is formed by repetition of the intermolecular inclusion. The hydroxyl group of the substituent group penetrates through the macrocyclic ring from the secondary hydroxyl side and is linked to an HO-6 group by a hydrogen bond. Comparison of intermolecular contacts of the substituent group indicates that the (S)-2-hydroxypropyl group is better fitted to the cavity than the (R)-2-hydroxy-propyl group.

Carbohydrate Conformation↗

PubMed1993

X-ray structure of monoclinic turkey egg lysozyme at 1.3 A resolution.

Monoclinic crystals of turkey egg lysozyme (TEL, E.C. 3.2.1.17) were obtained from 2.2 M ammonium sulfate solution at pH 4.2. They belong to space group P2(1) with unit-cell dimensions a = 38.07, b = 33.20, c = 46.12 A and beta = 110.1 degrees, and contain one molecule in the asymmetric unit (V(m) = 1.91 A(3) Da(-1)). The three-dimensional structure of TEL was solved by the method of multiple isomorphous replacement with anomalous scattering. Area detector data to 1.5 A resolution from native and heavy-atom derivatives were used for the structure determination. The structure was refined by the simulated-annealing method with diffraction data of 10-1.30 A resolution. The conventional R factor was 0.189. The root-mean-square deviations from ideal bond distances and angles were 0.016 A and 2.9 degrees, respectively. The backbone structure of TEL is very similar to that of hen egg lysozyme (HEL) and the difference in seven amino-acid residues does not affect the basic folding of the polypeptide chain. Except for the region from Gly101 to Gly104, the geometry of the active-site cleft is conserved between TEL and HEL. The Gly101 residue is located at the end of the sugar-binding site and the structural change in this region between TEL and HEL is considered to be responsible for the difference in their enzymatic properties.

Journal Article↗

PubMed1992

Dissection of the functional role of structural elements of tyrosine-63 in the catalytic action of human lysozyme.

The functional role of tyrosine-63 in the catalytic action of human lysozyme (EC 3.2.1.17) has been probed by site-directed mutagenesis. In order to identify the role of Tyr63 in the interaction with substrate, both the three-dimensional structures and the enzymatic functions of the mutants, in which Tyr63 was converted to phenylalanine, tryptophan, leucine, or alanine, have been characterized in comparison with those of the wild-type enzyme. X-ray crystallographical analysis of the mutant enzyme at not less than 1.77-A resolution indicated no remarkable change in tertiary structure except the side chain of 63rd residue. The conversion of Tyr63 to Phe or Trp did not change the enzymatic properties against the noncharged substrate (or substrate analogs) largely, while the conversion to Leu or Ala markedly reduced the catalytic activity to a few percent of wild-type enzyme. Kinetic analysis using p-nitrophenyl penta-N-acetyl-beta-(1----4)-chitopentaoside (PNP-(GlcNAc)5) as a substrate revealed that the reduction of activity should mainly be attributed to the reduction of affinity between enzyme and substrate. The apparent contribution of the phenolic hydroxyl group and the phenol group in the side chain of Tyr63 was estimated to 0.4 +/- 0.4 and 2.5 +/- 0.8 kcal mol-1, respectively. The result suggested that the direct contact between the planar side-chain group of Tyr63 and the sugar residue at subsite B is a major determinant of binding specificity toward a electrostatically neutral substrate in the catalytic action of human lysozyme.

Acetylglucosamine↗

PubMed1992

X-ray structural evidence for a local helix-loop transition in alpha-lactalbumin.

The three-dimensional structure of human alpha-lactalbumin for two crystal forms has been determined by x-ray analysis. One crystal (the form LT) was obtained at pH 4.2 and room temperature, while the other crystal (the form HT) was grown at pH 6.5 and 37 degrees C. The backbone structure for Lys1-Ile95 residues is almost conserved between the two structures as indicated by the root mean square difference of 0.30 A for the superposition of equivalent C alpha atoms. The calcium ion is surrounded by seven oxygen atoms of three carboxyl groups, two carbonyl groups, and two water molecules, which form a distorted pentagonal bipyramid in both structures. A large difference in polypeptide folding is found in the region of Leu96-Leu123 residues. Especially in the region of Trp104-Cys111 residues, a distorted alpha-helix is observed in the form HT while a loop structure is formed in the other crystal. The fact that the crystals of both forms appeared in the same batch at pH 6.5 and room temperature indicates that the human alpha-lactalbumin structure is highly fluctuated in solution and the folding and unfolding of the alpha-helix of Trp104-Cys111 residues are in equilibrium. Since the crystal of the form HT exclusively appeared around the physiological temperature, the structure of this form can be considered as the native structure. The partially unfolded structure in the form LT indicates that the local denaturation occurs even at room temperature.

Amino Acid Sequence↗