Scanning tunneling microscope observation of the phosphatidylserine domains in the phosphatidylcholine monolayer.
A mixed monolayer of 1,2-dihexanoyl-sn-glycero-3-phospho-l-serine (DHPS) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) on an 1-octanethiol-modified gold substrate was visualized on the nanometer scale using in situ scanning tunneling microscopy (STM) in aqueous solution. DHPS clusters were evident as spotty domains. STM enabled us to distinguish DHPS molecules from DHPC molecules depending on their electronic structures. The signal of the DHPS domains was abolished by neutralization with Ca(2+). The addition of the PS + Ca(2+)-binding protein of annexin V to the Ca(2+)-treated monolayer gave a number of spots corresponding to a single annexin V molecule.
†Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan.
Soichiro
S
Matsunaga
‡Lipid Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Taro
T
Yamada
‡Lipid Biology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Toshihide
T
Kobayashi
†Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan.
Maki
M
Kawai
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D017304:Annexin A5 / Q000737:chemistry; D002118:Calcium / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D016252:Microscopy, Scanning Tunneling; D010316:Particle Size; D010718:Phosphatidylserines / Q000737:chemistry*; D012996:Solutions; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014867:Water / Q000737:chemistry
C107840:1,2-dihexanoic-sn-glycero-3-phosphoserine; D017304:Annexin A5; D010718:Phosphatidylserines; D012996:Solutions; D013438:Sulfhydryl Compounds; D014867:Water; D015060:1,2-Dipalmitoylphosphatidylcholine; C402924:n-octanethiol; D006046:Gold; D002118:Calcium