CRYSTALLOGRAPHY POST-DOC POSITION WANTED

Mohan Srinivasan smohan at helix.nih.gov
Thu Mar 2 10:27:36 EST 1995


Hello!

	One of friends, who is a Crystallographer, with a
background in Biophysics is seeking a post-doctoral position
in Crystallography/Protein Crystallography. His CV is attached.
Interested people may contact either him directly or me at:
                                          smohan at helix.nih.gov

	Thanks!

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                         CURRICULUM VITAE



1.NAME AND ADDRESS  :

          N.SUKUMAR                    
          Department of Crystallography and Biophysics
          University of Madras, Guindy Campus
          Madras - 600 025, INDIA

          Phone  : 91-44-2351367 
          Telex  : 41 6376 UNOM IN
          Fax    : 91-44-415856 

2.DATE OF BIRTH AND AGE  :  June 25, 1966; 28 years 



3.MARITAL STATUS         :  Unmarried 



4.EDUCATIONAL QUALIFICATIONS  :

_________________________________________________________________

Degree    Institution      Fields             Year       Class
_________________________________________________________________


Ph.D.     University of    Crystallography    
          Madras           and Biophysics      (Thesis submitted)
                                                 



M.Phil.   University of    
          Madras               -do-           1989       FIRST
          


M.Sc.     University of    Biophysics         1988       FIRST &          
          Madras                                       FIRST RANK



B.Sc.     University of    Physics            1986       FIRST        
          Madras
      

 Title of the thesis : Structural Studies on Biologically and 
                       Medicinally Important Molecules 

________________________________________________________________

4. LANGUAGES KNOWN  :         Tamil (Mother Tongue)
                              English


5. RESEARCH / TEACHING EXPERIENCE  :
_________________________________________________________________

Duration     Institution                Designation  Nature of 
                                                     work
_________________________________________________________________


Nov. 1989-   School of Physics          Project      Research 
Feb. 1990    University of Hyderabad,   Assistant
             Hyderabad- 500 134, 
             India 


Feb. 1990-   Department of Crystallo-   University   Research and 
Dec. 1990    graphy and Biophysics,     Research     Teaching 
             University of Madras,      Fellow       (for M.Sc
             Madras - 600 025                         students) 
             India                                    


Jan. 1991-          -do-                CSIR- Senior      -do-
Till date                               Research 
                                        Fellow   

_________________________________________________________________


6. AWARDS:


1.   UGC SAP Merit Scholarship for the M.Sc students for the year 
     1986-88.

2.   First Rank Holder in M.Sc degree examination conducted 
     by the University of Madras.

3.   Senior Research Fellowship (SRF) from Council of  Scientific 
     and  Industrial  Research (CSIR), New Delhi, India. 


7. RESEARCH SPECIALISATION:

1.   Crystal   Structure   Determination   of   Medicinally   and 
     Biologically   important molecules.

2.   Data  Base  Analysis (Using both Cambridge  Structural  Data 
     Base (CSD) and Protein Data Bank (PDB).


8.   A BRIEF OUTLINE OF RESEARCH WORK:

     Since 1989, the applicant is working on the experimental and 
     theoretical [using Cambridge Structural Data Base (CSD)  and 
     Protein Data Bank (PDB)] aspects of Crystallography.  He has 
     gained good knowledge over the  experimental  techniques  of 
     crystal structure determination by X-ray  methods.   He  has  
     also gained  knowledge  of  mathematics,  Biostatistics  and 
     computer programming.  His research work falls  under    the  
     following categories.   

          (i)   Peptides  
          (ii)  Piperidines  
          (iii) Azabicyclononanes  
          (iv)  Steroids  
          (v)   Data Base Analysis  

          Summary of the Research work done : See Enclosure - A 


9.  PROGRAMS USED: 

     SHELXX86,  SHELX76,  SDP,  MULTAN,  PATSEE,  PARST,  GEOM78, 
     GEOM90, PLUTO, RETRIEVE, GKS SUBROUTINES


10. INSTRUMENTS USED:

     Data  for  the  all  the  compounds  have   been   collected 
     independantly  by  the  candidate  using  Enraf-Nonius  CAD4 
     instrument available in the department.  The applicant  used 
     MicroVAX  II   and   VAX730   computing   system   for   the 
     calculations. 


11. REFERENCES:

     1.   Dr.M.N. Ponnuswamy (Ph.D Supervisor)
          Department of Crystallography and Biophysics
          University of Madras
          Guindy campus
          Madras - 600 025, India
          Phone  : 91-44-2351367 (office)
          Fax    : 91-44-415856 

     2.   Dr.E. Subramanian
          Professor
          Department of Crystallography and Biophysics
          Guindy campus 
          University of Madras 
          Madras - 600 025, India
          Phone  : 91-44-4918512 (Residence)
          Fax    : 91-44-415856 

     3.   Dr. Vasantha Pattabhi
          Professor
          Department of Crystallography and Biophysics
          University of Madras
          Guindy campus
          Madras - 600 025, India
          Phone  : 91-44-4912081 (Residence)
          Fax    : 91-44-415856 


12.   RESEARCH PUBLICATIONS:


          Please See Enclosure - B 

                                                    Enclosure - A 
Summary of Research Work

          The work has been divided into three parts.  The  first  
part  consists  of the crystal structure  analysis  of  peptides. 
The following  dipeptides  containing  aliphatic  aminoacid   are 
taken  for  structural  study   to   find   out   their   adopted 
conformation as the statistical survey has  predicted  that  they 
are  having  high  propensity  for  extended  conformation.   (a)   
N-(t-butoxycarbonyl)-L-isoleucyl-L-alanine   Benzylester,     (b)  
N-(t-butoxycarbonyl)-  L-alanyl-(S-Benzyl)-  L-  cysteine  Methyl 
ester, (c)  N-(t-butoxycarbonyl)- L-isoleucyl- L-  valine  Methyl 
ester, (d)  N-(t-butoxycarbonyl)-e-N'-benzyloxy-carbonyl-L-lysyl- 
L-isoleucine  and  (e)  N-(t-butoxycarbonyl)-L-Valine   N-hydroxy 
succinimide  ester.   In  all  these  compounds, peptide  linkage  
is in trans conformation and the t-boc group  is in   trans-trans  
conformation.   In compounds  (a)  -  (d),   the  molecules adopt 
extended   conformation.    The   compound   (e)   contains   two 
crystallographically independent molecules (A  &   B)    in   the 
asymmetric unit.  The molecules  A  and  B  adopt   extended  and  
folded conformation respectively.   In general, all the aliphatic 
aminoacids containing peptides reported exhibit predominantly  an 
extended  conformation as predicted from the data base  analysis.  
However, the observed (m,j) angles in cases where the side  chain 
adopting the less preferred conformations suggests that the sheet 
forming  tendencies  may also depend on the  side  chain  rotamer 
conformational restrictions.          

          The second  part  consists  of  structural  studies  on 
piperidine derivatives.  The aim is to study  the  stereodynamics   
of piperidine derivatives and to  correlate  the  stereochemistry  
with their cancer/anticancer properties.  The following compounds 
have    been     solved     by   X-ray    diffraction    methods: 
(a) 2,6-di-(2-furyl)-3,5-dimethylpiperidin-4-one(DFMP), (b)2,6-di 
-(2-furyl)-3,5-dimethyl-N-nitrosopiperidin-4-one (DFMPNO),    (c) 
2,6-di(2-Thioenyl)-3,5-dimethylpiperidin-4-one (DTMP), (d) 2,6-di 
(o-chloro)phenyl-3,5-dimethyl-N-nitrosopiperidin-4-one (NOCDMPO),  
(e)  3,5- dimethyl- N-nitroso- 4-oximino- 2,6- diphenylpiperidin- 
4-one (DMNOH),  (f)  5-isopropyl-N-methyl-2,6-diphenyl-1- aza-oxa 
-thiaspirodecane (NMITK),   (g)    O-N- diacetyl-3- isopropyl-2,6 
-diphenylpiperidin-4-one oxime (IODA).  The  piperidine  ring  of 
compounds (a), (c) and (f) adopts chair conformation  while  (b), 
(d) and (e) exist in distorted boat conformation.   The  compound 
(g) is in twisted boat conformation.  The detailed conformational 
analysis  on  these  piperidine derivatives  indicates  that  the 
piperidine  rings  normally adopt a chair conformation  with  the 
substitutents  at equatorial orientation.  But, in some cases  it 
assumes the less favourable boat, twisted boat conformation  etc. 
so  as  to  avoid   steric   interactions   between   the   bulky 
substitutents.     

          A  review has been carried out to explain the  uses  of  
X-ray Crystallography  and the number of other possible  ways  to  
design new  drugs.  Forces involved in the molecular interactions  
which plays an important role in the mode of action of drugs also 
covered. The drug-DNA interaction has also been dealt   with   as 
many of the drugs are active at the DNA level.  The principle and 
techniques  used in the drug design also been covered.   In  this 
connection,  the use of computer graphics and  structure-activity 
relationship is analysed in some details.     


          Another  review  has been made on the two  classes   of  
anti-biotics  namely  anthracycline  and   ansamycin   class   of 
compounds  to derive  the  potential analogues of  compounds   in  
both  classes.  These  anthracycline  compounds  show  anti-tumor 
properties and used  in   the  treatment  of  cancer,  while  the 
ansamycin  compounds  show antiviral and antibacterial properties 
and are partcularly useful in  the  treatment   of  tuberculosis.  
In order  to  decipher  the relation   between  their   structure  
and  activity,   biological properties  of  compounds   such   as  
cellular  uptake,  metabolic changes, binding of  DNA  etc.  have 
been analysed.           


          The third part consists of  Cambridge  Crystallographic 
Structural Data Base analysis on  three  important  biomolecules, 
namely,  aminoacids,  nucleotides  and  carbohydrates.  (a)  Non- 
planarity of peptides and its sequence dependence, (b) Stretching 
of g(N-C  -C') angle in amino acids and peptides, (c) On  unusual 
observation  of eclipsed C  -NH   bond in aminoacids and peptides 
and   (d)   Molecular   aggregation     of    nucleotides     and    
carbohydrates    -    their  implication  to  evolution.     From   
the   analysis   of   (a)  and (b), we have  concluded  that   in  
general    the   non-planarity   of  peptides  or  stretching  of  
g(N-C -C')   angle   is   evoked  when there is a  net  gain   in   
energy   either    by    reducing    steric  interaction  or   by   
forming additional  hydrogen  bonds.  In  (c),  a  few  cases  of 
eclipsed C -NH   bond  in  aminoacids  and  peptides  have   been   
observed, eventhough  staggered  conformation  is  known  to   be  
energetically most   favoured.    An   attempt   to   study   the  
cause  for   such occurrences  and probability of observing  such 
eclipsed C  -  NH   bond in any one of  the  naturally  occurring 
aminoacids, have  been made.   Our analysis shows  that  hydrogen 
bonding alond is  enough to  cross the rotational  barrier  about 
C -NH    bond.   There   is  correlation  between  hydrogen  bond 
geometry and the deviation frpm staggered conformation of C  -  N 
bond is observed.  A study on the head-to-tail  sequence  of  the 
solid state  aggregation  suggests that  the  presence  of  water 
molecules do  not  have  significant effect  on  the arrangement. 
In (d), we  have  analysed   hydrogen   bonding     pattern    of   
nucleotides     and    carbohydrates.       An    analysis     on  
ribonucleotides  shows  that  the 3'...5'  hydrogen bond mediated  
aggregation   to   be   most   common  alignment.    The  2'...5'   
alignment   which   occurs   under   special   circumstances   in  
nature  is  found  to  be  second   choice.    An  analysis    of  
carbohydrates suggests that self-assembly of  these molecules  is 
not  conducive to the formation of polysaccharides of  the   type  
which   are  found in  present  day  living  organisms.   Further  
the   role of water molecules in  the  polymerisation   of  three 
important biomolecules have been analysed.  Implication  of these 
results to prebiotic polymerisation is discussed. 

                                                    Enclosure - B


I. RESEARCH PUBLICATIONS


1.   Crystal structure of a potential steroid intermediate - 
     C15H}0O} 
     N. Sukumar and Vasantha Pattabhi
     Acta Cryst.,  C47 , 400, 1991.


2.   Crystal Structure of LANTADENE - A, The Major  Triterpenoid 
     of Lantana Camara, Red Variety 
     Vasantha Pattabhi, N. Sukumar and O.P. Sharma 
     Acta Cryst., C47, 810, 1991.


3.   Molecular Aggregation in Nucleotides and Carbohydrates - 
     Their Implication to Prebiotic Polymerisation 
     N. Sukumar and Vasantha Pattabhi 
     J. Biosci., 17, 431, 1992. 


4.   Crystal Structure and  Conformation  N-(t-Butoxycarbonyl)-L-
     Valine N-Hydroxysuccinimide Ester 
     N. Sukumar,  M.N. Ponnuswamy and R. Jayakumar 
     Bull. Chem. Soc. Jpn., 66, 2101, 1993. 


5.   Crystal Structure and Conformation of  N-(t-butoxycarbonyl)- 
     L-isoleucyl-L-alanine benzylester 
     N. Sukumar, M.N. Ponnuswamy and R. Jayakumar 
     J. Cryst. Spec. Res., 23, 769, 1993. 


6.   Crystal and molecular structure  of  2,6-Di(o-chloro)phenyl- 
     3,5-dimethyl-N-nitrosopiperidin-4-one (NOCDMPO) 
     N. Sukumar, M.N. Ponnuswamy, J.C. Thenmozhiyal and 
     R. Jeyaraman     
     J. Cryst. Spec. Res., 23,  871,  1993. 


7.   Structural Investigation  of  2,6-Di-2-furyl-3,5-dimethyl-4- 
     piperidinone  and Its N-nitroso Derivative in  Solution  and 
     the Solid State - Influence of the Nitroso  Moiety   on  the 
     Conformation of the Piperidine ring and Orientation  of  Its 
     Substituents    
     N.  Sukumar,  M.N.   Ponnuswamy,   J.C.   Thenmozhiyal   and 
     R. Jeyaraman 
     Bull. Chem. Soc. Jpn. 67, 1069, 1994. 


8.   Crystal Structure and Conformation  of  N-(t-Butoxycarbonyl)- 
     L-alanyl-S-benzyl-L-Cysteine Methyl ester 
     N. Sukumar, M.N. Ponnuswamy and R. Jayakumar 
     Bull. Chem. Soc. Jpn., 67, (in press). 


9.   Crystal and Molecular Structure of 3,5-Dimethyl-N-nitroso-4- 
     Oximino-2,6-DiphenylPiperidin-4-one (DMNOH) 
     N.Sukumar, M.N.Ponnuswamy, R.Vijayalashmi and R.Jeyaraman 
     Z. fur Kristallographie (in press).


10.  Crystal Structure of 5-isopropyl-N-methyl-2,6-Diphenyl-1-Aza 
     -Oxa-Thiaspirodecane (NMITK) 
     N. Sukumar, M.N. Ponnuswamy, M. Sujatha and R. Jeyaraman 
     Communicated to J. Chem. Cryst. 


11.  Structural  Characterization  of  2,6-Di(2-Thioenyl)-   3,5- 
     Dimethyl piperidin-4-one in Solution and Solid State (DTMP) 
     N.Sukumar, M.N.Ponnuswamy, J.C.Thenmozhiyal and R.Jayaraman 
     Communicated to J. Chem. Cryst. 


12.  Sequence Dependence of Non-planarity  of  peptides  and  Its 
     Effect on Secondary Structures
     N.Sukumar and  Vasantha  Pattabhi.     
     Communicated  to  J.  Theor.  Biol.


13.  Stretching of g(N-C -C') Angle in Amino Acids and Peptides 
     N.Sukumar, D.Kumaran and M.N.Ponnuswamy (Under preparation)


14.  Crystal Structure and Conformation of N-(t-butoxycarbonyl) 
     -L-Isoleucyl-L-Valine methyl ester 
     N.Sukumar, M.N.Ponnuswamy and R.Jayakumar(Under Preparation) 


15.  Crystal Structure and Conformation of  N-(t-butoxycarbonyl)- 
     e-N'-benzyloxycarbonyl-L-lysyl-L-isoleucine     
     N.Sukumar, M.N.Ponnuswamy  and  R.Jayakumar 
     (Under Preparation).


16.  Crystal Structure  of  O-N-Diacetyl-3-isopropyl-2,6-diphenyl 
     piperidin-4-one Oxime (IODA)     
     N.Sukumar, M.N.Ponnuswamy, R.Vijayalashmi and R.Jeyaraman  
     (Under Preparation) 

II.  PAPERS PRESENTED/ATTENDED IN INTERNATIONAL CONFERENCES 

1.   Presented in Asian  Crystallographic  Association  (AsCA'92)  
     held  during Nov. 13-16, 1992 at Singapore. 

     Crystal Structure of  2,6-di(2-furyl)-3,5-dimethylpiperidin- 
     4-one 
     N.Sukumar, M.N.Ponnuswamy, J.C.Thenmozhiyal and R.Jayaraman 


2.   Presented in the "XVI International Congress and General  
     Assembly", International Union of Crystallography held  
     during 21-29, August, 1993 at Beijing, China. 

     (i)  Crystal Structure Studies on N-piperidin-4-ones 
          N.Sukumar, M.N.Ponnuswamy, R.Jeyarman and 
          J.C.Thenmozhiyal 

    (ii)  Crystal  Structure  and  Conformation  of  N-(t-Butoxy- 
          carbonyl-e- N'-Benzyloxycarbonyl- L-Lysyl- L-Isoleucyl- 
          Methyl ester 
          N. Sukumar, M.N. Ponnuswamy and R. Jayakumar 

   (iii)  Sequence Dependence of Non-planarity  of  Peptides  and 
          its Effects on Secondary Structures       
          N. Sukumar and Vasantha Pattabhi 


3.   Participated in the "Asian Region Seminar on Crystallography 
     in Molecular Biology"  held  during  December 9-14, 1993  at 
     Madras.


4.   Presented in the "4th Naples Workshop on Bioactive Peptides, 
     Conformation  Activity  in   Peptides:   Relationships   And 
     Interactions" held during May 22-25, 1994 at Naples, Italy. 

     Conformational Studies on Hydrophobic Aminoacids  Containing 
     Peptides 
     M.N.Ponnuswamy  and N.Sukumar.


5.   Presented   in   the   21       Crystallographic     Course: 
     Crystallography of Molecular Biology, held during May  27  - 
     June 5, 1994 at Erice,  Italy,  sponsored  by  International 
     Union of Crystallography. 

     Peptide Models For a-Sheet Conformation 
     M.N.Ponnuswamy and N.Sukumar

III.  PAPERS PRESENTED/ATTENDED IN NATIONAL CONFERENCES

1.   Presented  in the "XXI National Seminar on  Crystallography" 
     held during Dec. 27 - 29, 1989 at Bombay. 

     (i)  Occurrence of Eclipsed C - NH  Bond in Amino acids and 
          Peptides. 
          N. Sukumar and Vasantha Pattabhi

    (ii)  Crystal Structure of a Potential Steroid Intermediate 
          N. Sukumar and Vasantha Pattabhi


2.   Presented in "XXII National Seminar on Crystallography" held 
     during Dec. 26 - 28, 1990 at Calcutta. 

     Conformational Studies on Azabicyclononanes 
     N. Sukumar and M.N. Ponnuswamy 


3.   Presented in the " National  Symposium  on  Biophysics  with  
     special reference to Biomacromolecules",  held  during  Feb.   
     7 - 9, 1991 at Madras.  

     Crystallographic evidences for molecular aggregation and    
     their implication to Evolution 
     N. Sukumar and Vasantha Pattabhi


4.    Participated  in  the  "Seminar  on  NMR  Applications   in 
      Structural Chemistry and Structural  Biology"  held  during 
      January 27-28, 1992 at Madras.


5.   Presented  in  the National Symposium on "Recent  Trends  in 
     Molecular  & Medical Biophysics", held during Feb.  7  -  9, 
     1992 at Pune. 

     Non-Planarity of Peptides and its Sequence Dependence
     N. Sukumar and Vasantha Pattabhi


6.   Presented in "XXIII National Seminar on Crystallography",
     held during March, 23-25, 1992 at Jaipur. 

     Structure and Conformation of N-(t-boc)-L-Ile-L-Ala-Bzlc 
     N. Sukumar, M.N. Ponnuswamy and R. Jayakumar 


7.    Attended  workshop/Training   on   single   crystal   X-ray 
      Diffractometer held at the Department of Biophysics, AIIMS, 
      New Delhi from April 6-11, 1992. 





8.   Presented in the "XXIV National Seminar on Crystallography 
     and Microsymposium on the Crystallography of Superconducting 
     Materials" held during Oct. 20-22, 1992 at Jammu. 

     Crystal   structure   of   N- (t-butoxycarbonyl)- L-alanyl - 
     (s-benzyl)-L-cysteine Methyl ester 
     N. Sukumar, M.N. Ponnuswamy and R. Jayakumar 


9.   Presented in the "IBS XVIII National Symposium on  Molecular 
     and  Cellular  Biophysics"  held during Jan.  7-9,  1993  at 
     Anantapur. 

     Stretching of g(N-C -C') angle in Amino acids and Peptides 
     N. Sukumar, D. Kumaran and M.N. Ponnuswamy 


10.   Presented  in  the  "Discussion  Meeting  on   Biomolecular 
      Structure, Function and Interaction" held during September, 
      8-10, 1993 at Bangalore. 

     Conformational Studies on Aliphatic Amino acid Containing  
     Peptides
     N. Sukumar, D. Kumaran and M.N. Ponnuswamy


11.  Presented in the XXV  National  Seminar  on  Crystallography 
     held during Dec. 15-17, 1993 at Madras. 

     (i) Crystal Structure  of  3,5-Dimethyl-N-Nitroso-4-Oximino- 
         2,6-Diphenylpiperidin-4-one. 
         D.Kumaran, N.Sukumar and M.N.Ponnuswamy. 

    (ii) Conformational Studies on piperidin-4-ones.
         N.Sukumar and M.N.Ponnuswamy. 
















-- 
Mohan Srinivasan Ph.D                            | email: smohan at helix.nih.gov 
DCBDC/NCI/Bldg 37 Rm 2B10,NIH,9000 Rockville Pike| phone: 301 496 2202
Bethesda, MD 20892, USA                          | fax  : 301 402 1031





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