Protein Machineries Involved in the Attachment of Heme to Cytochrome c: Protein Structures and Molecular Mechanisms
نویسنده
چکیده
Cytochromes c (Cyt c) are ubiquitous heme-containing proteins, mainly involved in electron transfer processes, whose structure and functions have been and still are intensely studied. Surprisingly, our understanding of the molecular mechanism whereby the heme group is covalently attached to the apoprotein (apoCyt) in the cell is still largely unknown. This posttranslational process, known as Cyt c biogenesis or Cyt c maturation, ensures the stereospecific formation of the thioether bonds between the heme vinyl groups and the cysteine thiols of the apoCyt heme binding motif. To accomplish this task, prokaryotic and eukaryotic cells have evolved distinctive protein machineries composed of different proteins. In this review, the structural and functional properties of the main maturation apparatuses found in gram-negative and gram-positive bacteria and in the mitochondria of eukaryotic cells will be presented, dissecting the Cyt c maturation process into three functional steps: (i) heme translocation and delivery, (ii) apoCyt thioreductive pathway, and (iii) apoCyt chaperoning and heme ligation. Moreover, current hypotheses and open questions about the molecular mechanisms of each of the three steps will be discussed, with special attention to System I, the maturation apparatus found in gram-negative bacteria.
منابع مشابه
Preparation and biochemical characterisation of nanoconjugates of functionalized carbon nanotubes and cytochrome c
Objective(s): The present work deals with the preparation of nanobioconjugates based on the immobilization of cytochrome c (cyt c) on functionalized multi-wall carbon nanotubes (f-MWCNTs). The effect of the nanosupport and the immobilization procedure on the biochemical and structural characteristics of the immobilized protein was investigated. Methods: </strong...
متن کاملO-8: Molecular Mechanisms of Membrane Fusion Involved in Fertilization
Background: Assisted fertilization procedures are a currently widespread practice to regulate reproduction in humans and animals. The arising question is why the human being manipulating gametes to generate new individuals, if we do not understand yet the molecular mechanism of fertilization?. Successful completion of fertilization in mammals is dependent on three membrane fusion events: 1. the...
متن کاملImport of cytochrome c into mitochondria
The import of cytochrome c into mitochondria can be resolved into a number of discrete steps. Here we report on the covalent attachment of heme to apocytochrome c by the enzyme cytochrome c heme lyase in mitochondria from Neurospora crassa. A new method was developed to measure directly the linkage of heme to apocytochrome c. This method is independent of conformational changes in the protein a...
متن کاملStructural Characteristics of Stable Folding Intermediates of Yeast Iso-1-Cytochrome-c
Cytochrome-c (cyt-c) is an electron transport protein, and it is present throughout the evolution. More than 280 sequences have been reported in the protein sequence database (www.uniprot.org). Though sequentially diverse, cyt-c has essentially retained its tertiary structure or fold. Thus a vast data set of varied sequences with retention of similar structure and fun...
متن کاملCamel whey protein enhances lymphocyte survival by modulating the expression of survivin, bim/bax, and cytochrome C and restores heat stress-mediated pathological alteration in lymphoid organs
Objective(s): Heat stress (HS) is a catastrophic stressor that dampens immunity. The current study investigates the effect of dietary administration with camel whey protein (CWP) on apoptotic pathway caused by HS. Materials and Methods: Forty-five male mice were divided into three groups: a control group; HS group; and HS mice that were orally supplemented with CWP (CWP-HS group). Results: We f...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره 2013 شماره
صفحات -
تاریخ انتشار 2013