title: Structural insights into the efficient CO2-reducing activity of an NAD-dependent formate dehydrogenase from Thiobacillus sp. KNK65MA.
abstract: CO2 fixation is thought to be one of the key factors in mitigating global warming. Of the various methods for removing CO2, the NAD-dependent formate dehydrogenase from Candida boidinii (CbFDH) has been widely used in various biological CO2-reduction systems; however, practical applications of CbFDH have often been impeded owing to its low CO2-reducing activity. It has recently been demonstrated that the NAD-dependent formate dehydrogenase from Thiobacillus sp. KNK65MA (TsFDH) has a higher CO2-reducing activity compared with CbFDH. The crystal structure of TsFDH revealed that the biological unit in the asymmetric unit has two conformations, i.e. open (NAD(+)-unbound) and closed (NAD(+)-bound) forms. Three major differences are observed in the crystal structures of TsFDH and CbFDH. Firstly, hole 2 in TsFDH is blocked by helix α20, whereas it is not blocked in CbFDH. Secondly, the sizes of holes 1 and 2 are larger in TsFDH than in CbFDH. Thirdly, Lys287 in TsFDH, which is crucial for the capture of formate and its subsequent delivery to the active site, is an alanine in CbFDH. A computational simulation suggested that the higher CO2-reducing activity of TsFDH is owing to its lower free-energy barrier to CO2 reduction than in CbFDH.
authors: Department of Chemical Engineering, Kwangwoon University, Seoul 139-701, Republic of Korea.
authors: Hyunjun
authors: H
authors: Choe
authors: Department of Bio and Nano Chemistry, Kookmin University, Seoul 136-702, Republic of Korea.
authors: Jung Min
authors: JM
authors: Ha
authors: Department of Chemical Engineering, Kwangwoon University, Seoul 139-701, Republic of Korea.
authors: Jeong Chan
authors: JC
authors: Joo
authors: Department of Chemistry, Kwangwoon University, Seoul 139-701, Republic of Korea.
authors: Hyunook
authors: H
authors: Kim
authors: Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742, Republic of Korea.
authors: Hye-Jin
authors: HJ
authors: Yoon
authors: Department of Chemistry, Kwangwoon University, Seoul 139-701, Republic of Korea.
authors: Seonghoon
authors: S
authors: Kim
authors: Department of Bio and Nano Chemistry, Kookmin University, Seoul 136-702, Republic of Korea.
authors: Sang Hyeon
authors: SH
authors: Son
authors: Department of Chemistry, Faculty of Applied Sciences, Durban University of Technology, Durban, South Africa.
authors: Robert M
authors: RM
authors: Gengan
authors: Department of Bio and Nano Chemistry, Kookmin University, Seoul 136-702, Republic of Korea.
authors: Seung Taeg
authors: ST
authors: Jeon
authors: Department of Chemistry, Kwangwoon University, Seoul 139-701, Republic of Korea.
authors: Rakwoo
authors: R
authors: Chang
authors: Energy Research Center, Korea Institute of Science and Technology, Seoul, Republic of Korea.
authors: Kwang Deog
authors: KD
authors: Jung
authors: Department of Chemical Engineering, Kwangwoon University, Seoul 139-701, Republic of Korea.
authors: Yong Hwan
authors: YH
authors: Kim
authors: Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742, Republic of Korea.
authors: Hyung Ho
authors: HH
authors: Lee
mesh_terms: D002175:Candida / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D018360:Crystallography, X-Ray; D005560:Formate Dehydrogenases / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D011487:Protein Conformation; D013816:Thermodynamics; D013855:Thiobacillus / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism
chemical_list: D009243:NAD; D002245:Carbon Dioxide; D005560:Formate Dehydrogenases
keywords: CO2 reduction; NAD-dependent formate dehydrogenase; Thiobacillus sp. KNK65MA