Applications of Protein

 

Biological Applications of Protein

Defnition: Proteins are fundamental components of all living cells, performing a variety of biological tasks. Each protein has a particular 3D structure that determines its function. Protein structure is more conserved than protein sequence, and more closely related to function. o determine the 3!D structure of protein "e use some e#per e#perminantel minantel methods i.e. •

  $!rays crystallog crystallography raphy..

•

  %&'.

•

  (thers )e.g., neutron di*raction+.

Description:  

Protein Protein spli splicing cing is a natur naturally ally occur occurring ring pro process cess in "hic "hich h a

protein editor, called an intein, performs a molecular disappearing act by cutting itself out of a host protein in a traceless manner. n the t"o decades since its discovery, protein splicing has been harnessed for the development of several protein!engineering methods, such as $!ray crystallography and site!dir site! directe ected d mutag mutagenesi enesis s have fur furnishe nished d count countless less insig insights, hts, highl highlighti ighting ng ho" even the most by-antine of problems can yield to the right tools. his is perrha pe haps ps

be best st

ill llus ustr trat ated ed

by

con onsi side derring

pr pro ote tein in

po post sttr tran ansl slat atio iona nall

modications )P&s+. &ost, if not all, proteins are modied at some point/ it is nature0s "ay of imposing functional diversity on a single polypeptide chain

 he chemical modication of proteins can be accomplished throug thr ough h a var varie iety ty of me means, ans, inc includ luding ing bio biocon con1ug 1ugati ation on tec techni hnique ques, s, tot total al chemi che mical cal syn synthe thesis sis,, enen-ym yme!m e!medi ediate ated d react reaction ions, s, non nonsen sense se supp suppre ressi ssion on mutagenesis, and a variety of protein ligation methods. he latter group of  strate str ategie gies s inc includ lude e the pr prote otein in sem semisy isynth nthesi esis s me method thods s )de )dene ned d as tho those se "here the protein is manufactured from premade fragments one or both bein be ing g

reco comb mbiina nant nt

in

or orig igin in++

e#p #prresse ssed

pr pro ote teiin

li liga gattio ion n

)EP EP2+ 2+

an and d

trans

protein

!spli !sp lici cing ng )P )P +, +, h hes ese e are are un uniq ique ue tech techno nolo logi gies es in that that they they

 

comb co mbin ine e the the po" po"er er of bi biot otec echn hnol olog ogy, y, "h "hic ich h pr prov ovid ides es ac acce cessi ssibi bili lity ty to si sign gni ica cant nt am amou ount nts s of la larrge pr prot otei eins, ns, "i "ith th the the ve vers rsat atil ilit ity y of ch chem emic ical al synthesis, "hich allo"s the site!specic incorporation of almost any chemical modication into the target protein. E#pressed protein ligation )EP2+ allo"s a recombinant protein and a synthetic peptide to be linked together under mild aqueous conditions. he process involves a chemoselective reaction that yields a nal protein product "ith a native peptide bond bet"een its t"o building blocks. A biological role for pr prote otein in spl splici icing ng in uni unicel cellul lular ar or organ ganism isms s has prove proven n elusi elusive/ ve/ mod moder ern n inteins seem to be parasitic genetic elements that are inserted into the open rea eadi ding ng fram frames es of )u )usu sual ally ly++ es esse sent ntia iall ge gene nes. s. h his is frus frustr trat atio ion n as asid ide, e, the the process has found a multitude of applications in biotechnology and quickly attracted the interest of the peptide chemistry community, as 4!thioesters ure 6+. "ere identied as crucial intermediates in the reaction mechanism )5ig ) 5igu

 

5igure 6.  

&echanism of Protein plicing

 

Protein splicing )A+ and its variant protein

trans!splicing )B+.