Solution structure of a novel calcium binding protein, MTH1880, from Methanobacterium thermoautotrophicum.
MTH1880 is a hypothetical protein from Methanobacterium thermoautotrophicum, a target organism of structural genomics. The solution structure determined by NMR spectroscopy demonstrates a typical alpha + beta-fold found in many proteins with different functions. The molecular surface of the protein reveals a small, highly acidic pocket comprising loop B (Asp36, Asp37, Asp38), the end of beta2 (Glu39), and loop D (Ser57, Ser58, Ser61), indicating that the protein would have a possible cation binding site. The NMR resonances of several amino acids within the acidic binding pocket in MTH1880, shifted upon addition of calcium ion. This calcium binding motif and overall topology of MTH1880 differ from those of other calcium binding proteins. MTH1880 did not show a calcium-induced conformational change typical of calcium sensor proteins. Therefore, we propose that the MTH1880 protein contains a novel motif for calcium-specific binding, and may function as a calcium buffering protein.
Lee
Chang-Hun
CH
Department of Biochemistry, College of Science, Yonsei University, 134 Seodaemoon-Gu, Shinchondong, Seoul, Korea 120-749.
Jung
Jin-Won
JW
Yee
Adelinda
A
Arrowsmith
Cheryl H
CH
Lee
Weontae
W
D020816:Amino Acid Motifs; D000596:Amino Acids / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002118:Calcium / Q000737:chemistry*; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D017014:Methanobacterium / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D000596:Amino Acids; D001426:Bacterial Proteins; D002135:Calcium-Binding Proteins; D002118:Calcium