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Extremophiles (2016) 20:653661 DOI 10.1007/s00792-016-0854-6
ORIGINAL PAPER
http://orcid.org/0000-0003-0522-3206
Web End = Received: 22 December 2015 / Accepted: 14 June 2016 / Published online: 23 June 2016 Springer Japan 2016
penultimate step of the WoodLjungdahl pathway toward the formation of acetate. In silico analysis underlined that up to now beside of M. thermoacetica, only Sporomusa ovata contains only PDUL like classIII-PTAs but no other phosphotransacetylases or phosphotransbutyrylases (PTBs).
Keywords Phosphotransacetylase (PTA) Propanediol utilization protein (PDUL) Moorella thermoacetica WoodLjungdahl pathway
Introduction
Moorella thermoacetica (Collins et al. 1994), originally isolated as Clostridium thermoaceticum (Fontaine et al. 1942), is a model organism of acetogenic bacteria for the elucidation of the WoodLjungdahl pathway (Drake et al. 2008; Ragsdale and Pierce 2008), especially regarding enzyme structures and carbon ow (Drake and Daniel 2004). Thus, it has recently been shown that electron bifurcation provides the reductant for the energy-conserving step (Huang et al. 2012) similar to Acetobacterium woodii, the acetogenic model organism for energy conservation (Schuchmann and Mller 2014). M. thermoacetica was the rst acetogenic bacterium for which the genome has been sequenced (Pierce et al. 2008). Therein, many genes encoding enzymes of the WoodLjungdahl pathway, of the methyl (eastern) branch (e.g., formate dehydrogenase, moth_2312-moth_2314), as well as of the carbonyl (western) branch (e.g., carbon monoxide dehydrogenase, moth_1203) clearly could be identied. The WoodLjungdahl pathway leads into the synthesis of the key metabolite acetyl-CoA which is further converted via acetyl phosphate into acetate. Usually, these steps are catalyzed by a phosphotransacetylase (PTA) and an acetate kinase (ACK), respectively. While an ACK homologous protein containing a typical basic acetate
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Web End = Two propanediol utilizationlike proteins of Moorella thermoacetica with phosphotransacetylase activity
Ronja Breitkopf1 Ronny Uhlig2 Tina Drenckhan2 RalfJrg Fischer2http://orcid.org/0000-0003-0522-3206
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Abstract Moorella thermoacetica is one of the model acetogenic bacteria for the resolution of the WoodLjungdahl (acetyl-CoA) pathway in which CO2 is autotrophically assimilated yielding acetyl-CoA as central intermediate. Its further conversion into acetate relies on subsequent phosphotransacetylase (PTA) and acetate kinase reactions. However, the genome of M. thermoacetica contains no pta homologous gene. It has been speculated that the moth_0864 and moth_1181 gene products sharing similarities with an evolutionarily distinct phosphotransacylase involved in 1,2-propanediol utilization (PDUL) of Salmonella enterica act as PTAs in M....