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Presentations of some of my Teaching and Research Topics
Go Back to: My main Research Page   Science Education page     Methanotroph history       main Science Page   India Page
 
There are two sets of material here:
a) A summary of most of my work on methylotrophs given in a lecture in MAy 2024
b) The slides taken from my powerpoint presentations as a guest of Prof. Colin Murrel at the University of East Anglia They include many pictures of relevant scientists. This can be downloaded as Powerpoint presentations.
c) Lecture notes and slides for use of students on my Microbial Physiology course in SV University, India
. This material can be downloaded as a Word document or as a powerpoint presentation.
Methylotroph stories: my methylotroph research summarised in about 50 slides PPT
                    
The Methylotrophs and their investigators          PPT History of Methanotrophy
Oxidation of methane methanol & formaldehyde PPT The oxidation of methylated amines     PPT
The cytochromes and electron transport in methylotrophs      PPT Growth yields of methylotrophs            PPT
Carbon assimilation pathways                          PPT Completion of Serine cycle                   PPT
 
                 Link to: Teaching page on Microbial Physiology (SV University, India)
 
Methylotroph stories; dedicated to research students everywhere
















We published 2 papers together. The first described our new methylotroph and the next slide is the second.













The following slide was included to show what was lost when Boldrewood was demolished. This was my
room, complete with coffee machine and comfort. Murali with back showing was a 4th year medical student solving
a problem with his project and the other is a research student friend Leigh Felton.
Staff rooms were always availble for students to see members of staf.


The foolowing section is describes our work with MDH which was done some years later in collaboration with
Meenakshi Ghosh who came to Oxford from Calcutta to learn how to do X-ray crystallography of proteins.
She had previously had experience only with inorganic crystals. She needed a project so i provided it.


A wonderful collaboration; Meenakshi knew no biochemistry and i knew no crystallography and its interpretation

We made the mistake of relying on an 'expert' to asssy our enzyme for metal ion content and he found none.
After our Japanes friends showed that their Ethanol dehydrogenase contained calcium we found it in MDH.
Our work with a mutant lacking calcium enabled us to reconstitute it with strontium or barium.







The following slide shows the consensus sequence involved in the docking motifs which demonstrated to
Kashahara and Kato that they had a propeller structure which they wrongly interpreted as evidence for a quinoprotind



The mechanism involves an initial proton abstraction (by Asp 303) and a hydride transfer from the
methyl group of methanol. The quinol then passes its electrons one at a time to the specific
cytochrome electron acceptor. After a single electron has been transferred the free radical PQQH is stable,
and MDH is usuall isolated with PQQ in this form (Shown by Frank and Duine)
















3rd Story. Before we knew the structure of MDH we started working on how this enzyme with a novel
prosthetic group interacts with an electron transport chain so that the oxidation of methanol will be
coupled to ATP production.



NOTE: The ATP yield from methanol is very low but this does not matter because almost every atom of carbon
in these bacteria comes by way of this oxidation process so there is ATP to spare. Cell yields are not limited
(as in other bacteria) by ATP but by avaialbility of NADH. Matt Beardmore-Gray calculated that the large
amount of cytochrome and MDH in these bacteria is sufficient to cover the surface in a mono-molecular layer.


The solution of the unusual MDH structure helped us get an X-ray crystallogrqphy unit set up in the Department,
with the appointment of John Cooper and Steve Wood, and they helped solve the structure of the
two methylotroph cytochromes.








NOTE: the immense amount of difficult work on the genetics of our Methylobacterium by Karen Amaratunga and
Simon Dales led them to provide important evidence for all out ideas about structure, mechanism and
electron transport by a programme of site-directed mutagenesis.












 
 
 
Oxidation methane, methanol and formaldehyde      PPT  Top of Summaries
                                                                                           Return to Methanotroph History      

Movie of MDH Made by Stuart Findlow, University of Southampton, form the X-ray diffraction coordinates of MDH. If you cannot see movie when you click on arrrow then Go to YouTube clip

There is a separate set of slides for the special cytochromes of methylotrophs
Top of Oxidation
Top of Summaries      Return to History
The oxidation of methylated amines in methylotrophs          PPT      Top of Summaries
Top of oxidation of methylated amines
Top of summaries
The unusual cytochromes and electron transport in methylotrophs       PPT    Return to History  Top of summaries                      
 
Top of cytochromes
Top of summaries
The Methylotrophs     PPT                 Top of summaries               Return to History

Top of Methylotrophs
Top of Summaries

Growth yields of Methylotrophs             PPT             Top of Summaries        
Top of Growth yields
Top of Summaries
Carbon assimilation pathways         PPT          Top of Summaries       Return to History

Top of carbon assimilation                   
Top of summaries

For completion of the Serine cycle go to Serine Cycle completion
Completion of the Serine /Ethylmalonyl-CoA Cycle      PPT           Top of summaries             

Two other cycles for acetate assimilaion

Top of Serine/EMC cycle
Top of summaries
 

 

 

 

 

 

 

 

 

 


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