Catalytic site components common to both splicing steps of a group II intron.

نویسندگان

  • G Chanfreau
  • A Jacquier
چکیده

The splicing of group II introns occurs in two steps involving substrates with different chemical configurations. The question of whether these two steps are catalyzed by a single or two separate active sites is a matter of debate. Here, certain bases and phosphate oxygen atoms at conserved positions in domain V of a group II self-splicing intron are shown to be required for catalysis of both splicing steps. These results show that the active sites catalyzing the two steps must, at least, share common components, ruling out the existence of two completely distinct active sites in group II introns.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Metal ion catalysis during group II intron self-splicing: parallels with the spliceosome.

The identical reaction pathway executed by the spliceosome and self-splicing group II intron ribozymes has prompted the idea that both may be derived from a common molecular ancestor. The minimal sequence and structural similarities between group II introns and the spliceosomal small nuclear RNAs, however, have left this proposal in question. Mechanistic comparisons between group II self-splici...

متن کامل

The spliceosome catalyzes debranching in competition with reverse of the first chemical reaction.

Splicing of nuclear pre-mRNA occurs via two steps of the transesterification reaction, forming a lariat intermediate and product. The reactions are catalyzed by the spliceosome, a large ribonucleoprotein complex composed of five small nuclear RNAs and numerous protein factors. The spliceosome shares a similar catalytic core structure with that of fungal group II introns, which can self-splice u...

متن کامل

Host Factors Influencing the Retrohoming Pathway of Group II Intron RmInt1, Which Has an Intron-Encoded Protein Naturally Devoid of Endonuclease Activity

Bacterial group II introns are self-splicing catalytic RNAs and mobile retroelements that have an open reading frame encoding an intron-encoded protein (IEP) with reverse transcriptase (RT) and RNA splicing or maturase activity. Some IEPs carry a DNA endonuclease (En) domain, which is required to cleave the bottom strand downstream from the intron-insertion site for target DNA-primed reverse tr...

متن کامل

CRS1, a chloroplast group II intron splicing factor, promotes intron folding through specific interactions with two intron domains.

Group II introns are ribozymes that catalyze a splicing reaction with the same chemical steps as spliceosome-mediated splicing. Many group II introns have lost the capacity to self-splice while acquiring compensatory interactions with host-derived protein cofactors. Degenerate group II introns are particularly abundant in the organellar genomes of plants, where their requirement for nuclear-enc...

متن کامل

A glimpse into the active site of a group II intron and maybe the spliceosome, too.

The X-ray crystal structure of an excised group II self-splicing intron was recently solved by the Pyle group. Here we review some of the notable features of this structure and what they may tell us about the catalytic active site of the group II ribozyme and potentially the spliceosome. The new structure validates the central role of domain V in both the structure and catalytic function of the...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • Science

دوره 266 5189  شماره 

صفحات  -

تاریخ انتشار 1994