Preliminary structural studies on the MtxX protein from Methanococcus jannaschii.
Methanococcus jannaschii has an mtr gene cluster expressing N(5)-methyltetrahydromethanopterin:coenzyme M methyltransferase, which generates methane by reducing CO(2) with H(2) with concomitant energy production under strictly anaerobic conditions. Some methanogenic archaea also have an mtr gene-cluster homologue, the mtxXAH gene cluster. M. jannaschii has both an entire mtr gene cluster and a single mtxX gene instead of the whole mtxXAH gene cluster. A PSI-BLAST search, secondary-structure prediction and the absence of phosphotransacetylase activity in M. jannaschii strongly support the possibility that the MtxX protein constitutes a unique methyltransferase family. In this study, the MtxX protein from M. jannaschii has been cloned, expressed, purified and crystallized. Synchrotron data were collected to 2.9 A from a crystal of selenomethionine-substituted MtxX protein. The crystal belonged to the primitive hexagonal space group P6(1)22, with unit-cell parameters a = 54.9, b = 54.9, c = 341.1 A, beta = 120.0 degrees . A full structure determination is under way in order to provide insight into the structure-function relationship of this protein.
Shin
Dong Hae
DH
College of Pharmacy, Ewha Womans University, Seoul 120-750, Republic of Korea. dhshin55@ewha.ac.kr
D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003460:Crystallization; D018360:Crystallography, X-Ray; D017017:Methanococcus / Q000737:chemistry* / Q000201:enzymology / Q000235:genetics; D008969:Molecular Sequence Data; D010709:Phosphate Acetyltransferase / Q000737:chemistry / Q000172:deficiency
D019843:Archaeal Proteins; D010709:Phosphate Acetyltransferase