The reducible complexity of a mitochondrial molecular machine.
Molecular machines drive essential biological processes, with the component parts of these machines each contributing a partial function or structural element. Mitochondria are organelles of eukaryotic cells, and depend for their biogenesis on a set of molecular machines for protein transport. How these molecular machines evolved is a fundamental question. Mitochondria were derived from an alpha-proteobacterial endosymbiont, and we identified in alpha-proteobacteria the component parts of a mitochondrial protein transport machine. In bacteria, the components are found in the inner membrane, topologically equivalent to the mitochondrial proteins. Although the bacterial proteins function in simple assemblies, relatively little mutation would be required to convert them to function as a protein transport machine. This analysis of protein transport provides a blueprint for the evolution of cellular machinery in general.
Clements
Abigail
A
Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800, Australia.
Bursac
Dejan
D
Gatsos
Xenia
X
Perry
Andrew J
AJ
Civciristov
Srgjan
S
Celik
Nermin
N
Likic
Vladimir A
VA
Poggio
Sebastian
S
Jacobs-Wagner
Christine
C
Strugnell
Richard A
RA
Lithgow
Trevor
T
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D016935:Caulobacter crescentus / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity
D001426:Bacterial Proteins; D002352:Carrier Proteins; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins; D029701:Saccharomyces cerevisiae Proteins; C077016:TIM44 protein, S cerevisiae; C489671:TIMM44 protein, human