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16 Cards in this Set
- Front
- Back
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protein synthesis
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contain their own DNA, ribosomes, and other components required for protein synthesis
most are synthesized in cell nucleus and imported from the cytosol |
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two subcompartments
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matrix and inter-membrane space
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cristae
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extensive invaginations created by the inner membrane
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mitochondrial precursor proteins
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protein formed as whole component to distinguish from co translational uptake of protein
held in unfolded conformation through interactions with general chaperone proteins of Hsp70 family |
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protein translocators
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mediate protein translocation across the mitochondrial matrix
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TOM complex
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translocates proteins across outer membrane
translocase of outer membrane can work with TIM for translocation into matrix or alone to halt at outer membrane |
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TIM complex
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translocates proteins across inner membrane
translocase of inner membrane |
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SAM complex
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helps with the proper folding of beta barrel proteins
outer membrane |
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OXA complex
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helps mediate inner membrane proteins
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requirement of translocations (two)
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membrane potential
energy |
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energy requirement
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binding and release of Hsp and newly synthesized proteins require ATP hydrolysis
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membrane potential
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once passed through TOM and bound to TIM created by H+ gradient
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mitochondrial Hsp70
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in matrix, interacts with polypeptide when emerging from TIM
has high affinity for unfolded polypeptide chains can pass onto mitochondrial Hsp 60 |
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mitochondrial Hsp60
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helps unfolded proteins fold through ATP hydrolysis
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import into only inner membrane or inner membrane space
stop transfer seqeunce |
most common - only the N terminal signal sequence is translocated through TIM into matrix
stop transfer sequence - hydrophobic stretch of amino acids prevents further translocation, stop remains in membrane or signal sequence removed when directly after translocation through TIM, then guided to OXA complex which inserts in inner membrane space |
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inner vs outer membrane exclusion
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outer membrane contains porins, inner does not
outer therefore allows from diffusion to small such molecules such as CAC metabolites, therefore small family of specific metabolite transporters transfers vast number across inner membrane |
