Sequence basis of Barnacle Cement Nanostructure is Defined by Proteins with Silk Homology.
Barnacles adhere by producing a mixture of cement proteins (CPs) that organize into a permanently bonded layer displayed as nanoscale fibers. These cement proteins share no homology with any other marine adhesives, and a common sequence-basis that defines how nanostructures function as adhesives remains undiscovered. Here we demonstrate that a significant unidentified portion of acorn barnacle cement is comprised of low complexity proteins; they are organized into repetitive sequence blocks and found to maintain homology to silk motifs. Proteomic analysis of aggregate bands from PAGE gels reveal an abundance of Gly/Ala/Ser/Thr repeats exemplified by a prominent, previously unidentified, 43 kDa protein in the solubilized adhesive. Low complexity regions found throughout the cement proteome, as well as multiple lysyl oxidases and peroxidases, establish homology with silk-associated materials such as fibroin, silk gum sericin, and pyriform spidroins from spider silk. Distinct primary structures defined by homologous domains shed light on how barnacles use low complexity in nanofibers to enable adhesion, and serves as a starting point for unraveling the molecular architecture of a robust and unique class of adhesive nanostructures.
Chemistry Division, Code 6176, US Naval Research Laboratory, 4555 Overlook Ave, SW, Washington, DC, USA.
Christopher R
CR
So
Chemistry Division, Code 6176, US Naval Research Laboratory, 4555 Overlook Ave, SW, Washington, DC, USA.
Kenan P
KP
Fears
Center for Biomolecular Science and Engineering, Code 6900, US Naval Research Laboratory, 4555 Overlook Ave, SW, Washington, DC, USA.
Dagmar H
DH
Leary
Chemistry Division, Code 6176, US Naval Research Laboratory, 4555 Overlook Ave, SW, Washington, DC, USA.
Jenifer M
JM
Scancella
Center for Biomolecular Science and Engineering, Code 6900, US Naval Research Laboratory, 4555 Overlook Ave, SW, Washington, DC, USA.
Zheng
Z
Wang
Center for Biomolecular Science and Engineering, Code 6900, US Naval Research Laboratory, 4555 Overlook Ave, SW, Washington, DC, USA.
Jinny L
JL
Liu
Nicholas School of the Environment and Earth Sciences, Duke University Marine Laboratory, 135 Duke Marine Lab Rd, Beaufort, NC, USA.
Beatriz
B
Orihuela
Nicholas School of the Environment and Earth Sciences, Duke University Marine Laboratory, 135 Duke Marine Lab Rd, Beaufort, NC, USA.
Dan
D
Rittschof
Center for Biomolecular Science and Engineering, Code 6900, US Naval Research Laboratory, 4555 Overlook Ave, SW, Washington, DC, USA.
Christopher M
CM
Spillmann
Chemistry Division, Code 6176, US Naval Research Laboratory, 4555 Overlook Ave, SW, Washington, DC, USA.
Kathryn J
KJ
Wahl
D000818:Animals; D060829:Arthropod Proteins / Q000235:genetics* / Q000378:metabolism; D044602:Cellulases / Q000235:genetics / Q000378:metabolism; D005349:Fibroins / Q000235:genetics; D008970:Molecular Weight; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D017423:Sequence Analysis, RNA / Q000379:methods*; D017386:Sequence Homology, Amino Acid; D001468:Thoracica / Q000235:genetics / Q000378:metabolism*
D060829:Arthropod Proteins; D005349:Fibroins; D010088:Oxidoreductases; D044602:Cellulases