Crosslinking renders bacteriophage HK97 capsid maturation irreversible and effects an essential stabilization

Crosslinking renders bacteriophage HK97 capsid maturation irreversible and effects an essential... In HK97 capsid maturation, structural change (‘expansion’) is accompanied by formation of covalent crosslinks, connecting residue K169 in the ‘E‐loop’ of each subunit with N356 on another subunit. We show by complementation experiments with the K169Y mutant, which cannot crosslink, that crosslinking is an essential function. The precursor Prohead‐II passes through three expansion intermediate (EI) states en route to the end state, Head‐II. We investigated the effects of expansion and crosslinking on stability by differential scanning calorimetry of wild‐type and K169Y capsids. After expansion, the denaturation temperature (Tp) of K169Y capsids is slightly reduced, indicating that their thermal stability is not enhanced, but crosslinking effects a major stabilization (ΔTp, +11°C). EI‐II is the earliest capsid to form crosslinks. Cryo‐electron microscopy shows that for both wild‐type and K169Y EI‐II, most E‐loops are in the ‘up’ position, 30 Å from the nearest N356: thus, crosslinking in EI‐II represents capture of mobile E‐loops in ‘down’ positions. At pH 4, most K169Y capsids remain as EI‐II, whereas wild‐type capsids proceed to EI‐III, suggesting that crosslink formation drives maturation by a Brownian ratchet mechanism. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The EMBO Journal Wiley

Crosslinking renders bacteriophage HK97 capsid maturation irreversible and effects an essential stabilization

Loading next page...
 
/lp/wiley/crosslinking-renders-bacteriophage-hk97-capsid-maturation-irreversible-cnvSVNqssQ
Publisher
Wiley
Copyright
Copyright © 2013 Wiley Periodicals, Inc
ISSN
0261-4189
eISSN
1460-2075
DOI
10.1038/sj.emboj.7600613
Publisher site
See Article on Publisher Site

Abstract

In HK97 capsid maturation, structural change (‘expansion’) is accompanied by formation of covalent crosslinks, connecting residue K169 in the ‘E‐loop’ of each subunit with N356 on another subunit. We show by complementation experiments with the K169Y mutant, which cannot crosslink, that crosslinking is an essential function. The precursor Prohead‐II passes through three expansion intermediate (EI) states en route to the end state, Head‐II. We investigated the effects of expansion and crosslinking on stability by differential scanning calorimetry of wild‐type and K169Y capsids. After expansion, the denaturation temperature (Tp) of K169Y capsids is slightly reduced, indicating that their thermal stability is not enhanced, but crosslinking effects a major stabilization (ΔTp, +11°C). EI‐II is the earliest capsid to form crosslinks. Cryo‐electron microscopy shows that for both wild‐type and K169Y EI‐II, most E‐loops are in the ‘up’ position, 30 Å from the nearest N356: thus, crosslinking in EI‐II represents capture of mobile E‐loops in ‘down’ positions. At pH 4, most K169Y capsids remain as EI‐II, whereas wild‐type capsids proceed to EI‐III, suggesting that crosslink formation drives maturation by a Brownian ratchet mechanism.

Journal

The EMBO JournalWiley

Published: Jun 6, 2005

Keywords: ; ; ; ;

References

  • Proteolytic and conformational control of virus capsid maturation: the bacteriophage HK97 system
    Conway, JF; Duda, RL; Cheng, N; Hendrix, RW; Steven, AC
  • The identification of complex genotypes in bacteriophage T4.I. Methods
    Doermann, AH; Boehner, L
  • Structural transitions during bacteriophage HK97 head assembly
    Duda, RL; Hempel, J; Michel, H; Shabanowitz, J; Hunt, D; Hendrix, RW
  • Genetic basis of bacteriophage HK97 prohead assembly
    Duda, RL; Martincic, K; Hendrix, RW
  • Evidence that a local refolding event triggers maturation of HK97 bacteriophage capsid
    Lee, KK; Gan, L; Tsuruta, H; Hendrix, RW; Duda, RL; Johnson, JE
  • Structure and morphogenesis of bacteriophage T4
    Leiman, PG; Kanamaru, S; Mesyanzhinov, VV; Arisaka, F; Rossmann, MG
  • Assembly‐dependent conformational changes in a viral capsid protein. Calorimetric comparison of successive conformational states of the gp23 surface lattice of bacteriophage T4
    Ross, PD; Black, LW; Bisher, ME; Steven, AC

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create folders to
organize your research

Export folders, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off