Crystal structures of artificial metalloproteins: tight binding of FeIII(Schiff-Base) by mutation of Ala71 to Gly in apo-myoglobin

Apo-myoglobin (apo-Mb) and apo-A71GMb were successfully reconstituted with FeIII(salophen) (1) (salophen = N,N'-bis(salicylidene)-1,2-phenilenediamine), Fe(III)(3,3'-Me2-salophen) (2), and FeIII(5,5'-t-Bu2-salophen) (3). The crystal structure of 2.apo-A71GMb shows the tight binding of the complex in the Mb cavity, while in wild-type apo-Mb it is highly disordered due to the steric repulsion with Ala71. Furthermore, the structure of 2.apo-A71GMb suggests a possible accommodation of a small substrate in the cavity. In fact, the cyanide association rate constant of 2.apo-A71GMb is 216-fold larger compared to that of 2.apo-Mb. These results provide us principles for the noncovalent fixation of synthetic metal cofactors at the desired positions in protein matrixes.     

Zero- and low-field μ+ spin relaxation behavior in MnSi

Conclusion As is demonstrated in the present work, the zero-field technique is a powerful method in studying diffusion/trapping of the ⁺, especially for the case of slow hopping. In the case of MnSi, the hopping time _c has been determined to be longer than 20 sec, with the width of the nuclear random fields / = 3.80 ± 0.4 Oe. The role of the ⁺ in low-field relaxation studies is unique, since it provides information inaccessible to NMR techniques.Work supported by Japan Society for the Promotion of Science, the Toray Science Foundation, the Grant-in-Aid of the Japanese Ministry of Education, Culture and Science, and the Atomic Energy Control Board and National Research Council of Canada.     

Cohen–Macaulayness of almost complete intersection tangent cones

We prove that associated graded rings of complete intersection monomial curves of codimension three are Cohen–Macaulay if their defining ideals are generated by at most four elements.     

Generalized positive continuous additive functionals of multidimensional Brownian motion and their associated Revuz measures

We extend the notion of positive continuous additive functionals of multidimensional Brownian motions to generalized Wiener functionals in the setting of Malliavin calculus. We call such a functional a generalized PCAF. The associated Revuz measure and a characteristic of a generalized PCAF are also extended adequately. By making use of these tools a local time representation of generalized PCAFs is discussed. It is known that a Radon measure corresponds to a generalized Wiener functional through the occupation time formula. We also study a condition for this functional to be a generalized PCAF and the relation between the associated Revuz measure of the generalized PCAF corresponding to Radon measure and this Radon measure. Finally we discuss a criterion to determine the exact Meyer–Watanabe’s Sobolev space to which this corresponding functional belongs.